Photochromic polyacrylate material, photochromic adhesive sheet and preparation method thereof

Abstract

The invention discloses a photochromic polyacrylate material, a photochromic adhesive sheet and a preparation method of the photochromic polyacrylate material. The photochromic polyacrylate material is prepared from the following raw material components in parts by weight through free radical copolymerization: 2.5-10 parts of a photochromic monomer; 6-24 parts of a soft monomer; 9-36 parts of a hard monomer; 3-12 parts of a functional monomer; 0.07 to 0.28 part of an initiator; and 30-120 parts of a first solvent. According to the invention, a photochromic group is connected to a polymer main chain in a chemical bond form in a copolymerization manner, so that the problem that toner is easy to separate out in physical blending is thoroughly solved, and the uniformity and stability of the material are remarkably improved; the photochromic polyacrylate material prepared by the preparation method disclosed by the invention is excellent in photochromic performance and strong in durability, and can still keep stable color change after multiple light cycles; the preparation method disclosed by the invention is simple to operate and high in feasibility, industrial production is easy to realize, and powerful technical support is provided for practical application of the photochromic material.

Description

Technical Field

[0001] This invention relates to the field of photochromic materials, and particularly to a photochromic polyacrylate material, a photochromic adhesive sheet, and a method for preparing the same. Background Technology

[0002] Photochromic materials are a class of functional materials that change color under light irradiation, and they have broad application prospects in fields such as anti-counterfeiting, displays, and sensors. Combining photochromic materials with polymer matrices to prepare photochromic composite materials is an important way to realize their practical applications. However, traditional physical blending methods suffer from problems such as poor compatibility between photochromic pigments and polymer matrices, and easy precipitation, leading to unstable photochromic properties and poor durability of the materials.

[0003] Traditional photochromic coatings disperse pigments in acrylic ester adhesives through physical blending, but this method suffers from the following drawbacks: (1) severe phase separation: the large polarity difference between the pigments and the polymer matrix leads to precipitation during storage and use; (2) poor weather resistance: physically bonded pigments are easily degraded under ultraviolet light, resulting in a low number of color-changing cycles; (3) insufficient adhesion: ungrafted pigments migrate on the substrate surface, causing coating failure. Copolymerizing photochromic units onto the acrylic ester polymer backbone is an advanced method to overcome the precipitation problem of physical blending and obtain a highly uniform and stable system. Although it faces challenges such as monomer synthesis and performance regulation, its performance advantages (no migration, high uniformity, and designable performance) make it a promising and valuable material for high-performance photochromic materials (such as smart windows, anti-counterfeiting inks, advanced optical lenses, and sensors).

[0004] Therefore, developing a preparation method that can effectively solve the compatibility problem between photochromic pigments and polymer matrices is of great practical significance. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a photochromic polyacrylate material, a photochromic adhesive sheet and a method for preparing the same, in order to address the shortcomings of the prior art.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: In its first aspect, the present invention provides a photochromic polyacrylate material, which is obtained by free radical copolymerization of the following raw material components in parts by weight: Photochromic monomer 2.5-10 parts; 6-24 parts of soft monomer; 9-36 parts of hard monomer; 3-12 parts of functional monomers; Initiator 0.07-0.28 parts; 30-120 parts of the first solvent; The photochromic monomer is obtained by reacting a photochromic compound containing hydroxyl groups with an acrylate monomer containing isocyanate groups in the presence of a catalyst.

[0007] Preferably, the raw materials for preparing the photochromic monomer include, by weight: 5-20 parts of a photochromic compound containing hydroxyl groups, 6-24 parts of an acrylate monomer containing isocyanate groups, 0.05-0.2 parts of a catalyst, and 25-100 parts of a second solvent.

[0008] Preferably, the photochromic compound containing hydroxyl groups is at least one of spiropyran compounds, spiroxazine compounds, or succinic anhydride compounds.

[0009] Preferably, the acrylate monomer containing the isocyanate group is at least one of ethyl isocyanate methacrylate (IMA) or ethyl isocyanate acrylate.

[0010] Preferably, the catalyst is dibutyltin dilaurate and the second solvent is toluene.

[0011] Preferably, the preparation method of the photochromic monomer is as follows: a photochromic compound containing hydroxyl groups is added to a second dissolution solution and stirred to dissolve. Then, an acrylate monomer containing isocyanate groups and a catalyst are added, and the reaction is carried out at 50-70°C for 3-12 hours. After the reaction is completed, the mixture is cooled to room temperature, filtered, and the solvent is removed by rotary evaporation of the filtrate to obtain the photochromic monomer.

[0012] Preferably, the soft monomer comprises one or more of the following: ethyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, octadecyl acrylate, and ethoxyethoxyethyl acrylate. The hard monomers include one or more of the following: methyl methacrylate, ethyl methacrylate, acrylonitrile, acryloylmorpholine, and N-vinylpyrrolidone; The functional monomers include one or more of the following: 2-hydroxyethyl acrylate, hydroxybutyl acrylate, acrylamide, acrylic acid, and glycidyl acrylate; The initiator is one or both of azobisisobutyronitrile and azobisisoheptanenitrile.

[0013] A second aspect of the present invention provides a method for preparing the photochromic polyacrylate material as described above, comprising the following steps: The soft monomer, hard monomer, functional monomer, and part of the first solvent are mixed and stirred under nitrogen at 50-70°C for at least 30 minutes. The first part of the initiator is added, and the reaction is carried out at 60-63°C for 1.5-6 hours. The second part of the initiator is added, and the reaction is continued for 1.5-6 hours. The temperature is raised to 65-68°C, and the remaining third part of the initiator is added. The reaction is carried out for 1.5-6 hours. After cooling, the remaining first solvent is added and mixed evenly to obtain the photochromic polyacrylate material.

[0014] In a third aspect, the present invention provides a photochromic adhesive sheet, which is obtained by coating and curing a photochromic adhesive liquid onto a substrate. The photochromic adhesive liquid comprises the following raw material components by weight: 100 parts of the photochromic polyacrylate material as described above, 0.03-0.12 parts of thermosetting agent, 0.015-0.06 parts of tackifier, and 0.015-0.06 parts of catalyst.

[0015] Preferably, the photochromic adhesive sheet is prepared by the following method: Photochromic polyacrylate material, thermosetting agent, tackifier and catalyst are mixed evenly to obtain photochromic adhesive liquid; The photochromic adhesive is evenly coated on the surface of the substrate, dried, and then a release film is attached to the adhesive surface and cured to obtain the photochromic adhesive sheet.

[0016] The beneficial effects of this invention are: This invention provides a photochromic polyacrylate material, a photochromic adhesive sheet, and a method for preparing the same. By copolymerizing, the photochromic groups are chemically bonded to the polymer backbone, which completely solves the problem of easy precipitation of pigments in physical blending and significantly improves the uniformity and stability of the material. The photochromic polyacrylate material prepared by this invention has excellent photochromic properties and strong durability, and can still maintain a stable color change after multiple light cycles. The preparation method of this invention is simple to operate, highly feasible, and easy to industrialize, providing strong technical support for the practical application of photochromic materials. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to embodiments, so that those skilled in the art can implement it based on the description.

[0018] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0019] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following examples are commercially available. For examples where specific conditions are not specified, conventional conditions or conditions recommended by the manufacturer are followed. For reagents or instruments whose manufacturers are not specified, they are all commercially available products.

[0020] This invention provides a photochromic polyacrylate material, which is obtained by free radical copolymerization of the following raw material components in parts by weight: Photochromic monomer 2.5-10 parts; 6-24 parts of soft monomer; 9-36 parts of hard monomer; 3-12 parts of functional monomers; Initiator 0.07-0.28 parts; 30-120 parts of the first solvent; The photochromic monomer is obtained by reacting a photochromic compound containing hydroxyl groups with an acrylate monomer containing isocyanate groups in the presence of a catalyst.

[0021] In a preferred embodiment, the raw materials for preparing the photochromic monomer include, by weight: 5-20 parts of a photochromic compound containing hydroxyl groups, 6-24 parts of an acrylate monomer containing isocyanate groups, 0.05-0.2 parts of a catalyst, and 25-100 parts of a second solvent.

[0022] In a preferred embodiment, the photochromic compound containing hydroxyl groups is at least one of spiropyran compounds, spiroxazine compounds, or succinic anhydride compounds.

[0023] In a preferred embodiment, the acrylate monomer containing the isocyanate group is at least one of ethyl isocyanate methacrylate (IMA) or ethyl isocyanate acrylate.

[0024] In a preferred embodiment, the catalyst is dibutyltin dilaurate and the second solvent is toluene.

[0025] In a preferred embodiment, the photochromic monomer is prepared by adding a photochromic compound containing hydroxyl groups to a second solvent, stirring to dissolve, then adding an acrylate monomer containing isocyanate groups and a catalyst, reacting at 50-70°C for 3-12 hours, cooling to room temperature after the reaction, filtering, and removing the solvent by rotary evaporation of the filtrate to obtain the photochromic monomer.

[0026] In a preferred embodiment, the soft monomer comprises one or more of the following: ethyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, octadecyl acrylate, and ethoxyethoxyethyl ethyl acrylate. In a preferred embodiment, the hard monomer comprises one or more of the following: methyl methacrylate, ethyl methacrylate, acrylonitrile, acryloylmorpholine, and N-vinylpyrrolidone; In a preferred embodiment, the functional monomer includes one or more of the following: 2-hydroxyethyl acrylate, hydroxybutyl acrylate, acrylamide, acrylic acid, and glycidyl acrylate; In a preferred embodiment, the initiator is one or both of azobisisobutyronitrile and azobisisoheptanenitrile.

[0027] The present invention also provides a method for preparing the photochromic polyacrylate material as described above, comprising the following steps: The soft monomer, hard monomer, functional monomer, and part of the first solvent are mixed and stirred under nitrogen at 50-70°C for at least 30 minutes. The first part of the initiator is added, and the reaction is carried out at 60-63°C for 1.5-6 hours. The second part of the initiator is added, and the reaction is continued for 1.5-6 hours. The temperature is raised to 65-68°C, and the remaining third part of the initiator is added. The reaction is carried out for 1.5-6 hours. After cooling, the remaining first solvent is added and mixed evenly to obtain the photochromic polyacrylate material.

[0028] The present invention also provides a photochromic adhesive sheet, which is obtained by coating and curing a photochromic adhesive liquid onto a substrate. The photochromic adhesive liquid comprises the following raw material components by weight: 100 parts of the photochromic polyacrylate material as described above, 0.03-0.12 parts of thermosetting agent, 0.015-0.06 parts of tackifier, and 0.015-0.06 parts of catalyst.

[0029] In a preferred embodiment, the photochromic adhesive sheet is prepared by the following method: Photochromic polyacrylate material, thermosetting agent, tackifier and catalyst are mixed evenly to obtain photochromic adhesive liquid; The photochromic adhesive is evenly coated on the surface of the substrate, dried, and then a release film is attached to the adhesive surface and cured to obtain the photochromic adhesive sheet.

[0030] The above is the general concept of the present invention. Based on this, detailed embodiments and comparative examples are provided below to further illustrate the present invention.

[0031] Example 1 A photochromic polyacrylate material, prepared by the following method: S1. Preparation of photochromic monomers: In a four-necked flask equipped with a stirrer, thermometer, and condenser, 10 g of 6-hydroxyspiropyran (SP-OH) and 50 mL of anhydrous toluene were added and stirred until dissolved. Then, 12 g of ethyl isocyanate methacrylate (IMA) (an acrylate monomer containing isocyanate groups) and 0.1 g of dibutyltin dilaurate (DBTDL) catalyst were added, and the reaction was carried out at 60 °C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the solvent was removed from the filtrate using a rotary evaporator to obtain a light yellow solid product, a photochromic monomer, denoted as SP-IMA.

[0032] S2. Preparation of photochromic polyacrylate materials: Accurately weigh 43 parts by weight of ethyl acetate, 12 parts by weight of 2-ethylethyl acrylate, 13 parts by weight of methyl methacrylate (MMA), 2 parts by weight of acrylmorpholine, 4 parts by weight of hydroxybutyl acrylate, 2 parts by weight of acrylic acid, and 5 parts by weight of SP-IMA. Mix them evenly and place them in a four-necked flask equipped with a stirrer, condenser, and nitrogen tube. Purge with nitrogen and stir at 60°C for 30 minutes. Add 0.04 parts by weight of initiator AIBN and react at 60-63°C for 3 hours. Then add another 0.04 parts by weight of initiator AIBN and react for another 3 hours. Then raise the temperature to 65-68°C and add another 0.06 parts by weight of initiator AIBN and react for another 3 hours. After cooling, dilute with 17 parts by weight of ethyl acetate to obtain the photochromic polyacrylate material.

[0033] A photochromic adhesive sheet, the preparation method of which includes the following steps: 1. Weigh 100 parts by weight of photochromic polyacrylate material, and add 0.01 parts of isocyanate curing agent (specifically toluene diisocyanate), 0.005 parts of aluminum acetylacetonate curing agent, 0.03 parts of tackifier (specifically terpene resin), and 0.03 parts of catalyst (specifically dibutyltin dilaurate) in sequence. Mix and stir evenly to obtain photochromic adhesive liquid. 2. Apply photochromic adhesive to the release surface of the release film, control the wet adhesive thickness to 50μm, bake at 120℃ for 3min, and then attach the release film to its surface. 3. After curing at 55℃ for 2 days, a photochromic adhesive sheet was obtained, denoted as P1.

[0034] Example 2 The only difference between this example and Example 1 is that in the preparation method of the photochromic polyacrylate material, methyl methacrylate (MMA) is replaced with a mixture of methyl methacrylate (MMA) and butyl acrylate (BA) (in the mixture, the mass ratio of MMA:BA is 3:1); the final photochromic adhesive sheet is denoted as P2.

[0035] Example 3 The only difference between this example and Example 1 is that in the preparation method of the photochromic polyacrylate material, methyl methacrylate (MMA) is replaced with a mixture of methyl methacrylate (MMA) and lauryl acrylate (in the mixture, the mass ratio of MMA to lauryl acrylate is 4:1); the final photochromic adhesive sheet is denoted as P3.

[0036] Example 4 The only difference between this example and Example 1 is that in the preparation method of the photochromic polyacrylate material, 6-hydroxyspiroxazine (SO-OH) is used instead of 6-hydroxyspiropyran (SP-OH) to obtain the photochromic monomer denoted as SO-IMA, with a yield of 82%; in the preparation method of the photochromic polyacrylate material, SO-IMA is used instead of SP-IMA; and the final photochromic adhesive sheet is denoted as P4.

[0037] Comparative Example 1 A photochromic adhesive sheet, wherein the photochromic polyacrylate adhesive sheet is prepared by a physical blending method, the specific steps of which are as follows: S1. Accurately weigh 48 parts by weight of ethyl acetate, 12 parts by weight of 2-ethylethyl acrylate, 13 parts by weight of methyl methacrylate (MMA), 2 parts by weight of acryloylmorpholine, 4 parts by weight of hydroxybutyl acrylate, and 2 parts by weight of acrylic acid. Mix them evenly and place them in a four-necked flask equipped with a stirrer, condenser, and nitrogen tube. Purge with nitrogen and stir at 60°C for 30 minutes. Then add 0.04 parts by weight of initiator AIBN and react at 60-63°C for 3 hours. Then add another 0.04 parts by weight of initiator AIBN and react for another 3 hours. Then raise the temperature to 65-68°C and add another 0.06 parts by weight of initiator AIBN and react for another 3 hours. After cooling, dilute with 17 parts by weight of ethyl acetate to obtain polyacrylate material.

[0038] S2. Weigh 100 parts of polyacrylate material by weight, and add 5 parts of SP-OH, 0.025 parts of isocyanate curing agent (specifically toluene diisocyanate), 0.005 parts of aluminum acetylacetonate curing agent, 0.03 parts of tackifier (specifically terpene resin), and 0.03 parts of catalyst (specifically dibutyltin dilaurate) in sequence to obtain photochromic adhesive liquid; S3. Apply photochromic adhesive liquid to the release surface of the release film, control the wet adhesive thickness to be 50μm, bake at 120℃ for 3min, and then attach the release film to its surface; cure at 55℃ for 2 days to obtain the photochromic adhesive sheet, denoted as C1.

[0039] Comparative Example 2 A photochromic polyacrylate material, wherein unmodified spiropyran is directly involved in copolymerization, and the preparation method is as follows: Accurately weigh 43 parts by weight of ethyl acetate, 12 parts by weight of 2-ethylethyl acrylate, 13 parts by weight of methyl methacrylate (MMA), 2 parts by weight of acryloylmorpholine, 4 parts by weight of hydroxybutyl acrylate, 2 parts by weight of acrylic acid, and 5 parts by weight of SP-OH. Mix them evenly and place them in a four-necked flask equipped with a stirrer, condenser, and nitrogen tube. Purge with nitrogen and stir at 60°C for at least 30 minutes. Add 0.04 parts by weight of initiator AIBN and react at 60-63°C for 3 hours. Then add another 0.04 parts by weight of initiator AIBN and react for another 3 hours. Then raise the temperature to 65-68°C and add another 0.06 parts by weight of initiator AIBN and react for another 3 hours. After cooling, dilute with 17 parts by weight of ethyl acetate to obtain the photochromic polyacrylate material.

[0040] A photochromic adhesive sheet, the preparation method of which includes the following steps: 1. Weigh 100 parts of polyacrylate material by weight, and add 0.025 parts of isocyanate curing agent (specifically toluene diisocyanate), 0.005 parts of aluminum acetylacetonate curing agent, 0.03 parts of tackifier (specifically terpene resin), and 0.03 parts of catalyst (specifically dibutyltin dilaurate) in sequence to obtain photochromic adhesive liquid;

[0041] 2. Apply photochromic adhesive to the release surface of the release film, control the wet adhesive thickness to 50μm, bake at 120℃ for 3min, and then attach the release film to its surface. 3. After curing at 55℃ for 2 days, a photochromic adhesive sheet was obtained, denoted as C2.

[0042] Performance testing (1) Ultraviolet-Visible Spectroscopy Analysis The photochromic adhesive sheets prepared in Examples 1-4 and Comparative Examples 1-2 were subjected to UV-Vis spectrometry to measure the changes in their absorption spectra before and after UV irradiation. The results are shown in Table 1 below: Table 1 (2) Pigment precipitation test The photochromic adhesive sheets prepared in Examples 1-4 and Comparative Examples 1-2 were immersed in toluene and left at room temperature for 2 hours. The absorbance of the solution at the maximum absorption wavelength was then measured using a UV-Vis spectrometer, and the amount of pigment precipitated was calculated. The results are shown in Table 2 below. Table 2 (3) Fatigue resistance test The fatigue resistance of the photochromic adhesive sheets prepared in Examples 1-4 and Comparative Examples 1-2 was tested. They were subjected to 100 cycles of alternating irradiation with ultraviolet light (365 nm, 10 mW / cm²) and visible light, with each irradiation lasting 1 minute. The absorbance change at the maximum absorption wavelength was recorded during the test, and the absorbance retention rate was calculated. The results are shown in Table 3 below: Table 3 (4) Mechanical property testing The photochromic adhesive sheets prepared in Examples 1-4 and Comparative Examples 1-2 were cut into 2.5 cm wide strips. The testing method followed the international standard ASTM D3330, "Test Standard for Peel Strength of Pressure-Sensitive Adhesive Tapes". The test method involved bonding the strip to a test steel plate at room temperature for 20 minutes, and recording the average adhesive force required to peel the strip from the test panel, expressed as gf / 25 mm. The results are shown in Table 4 below. Table 4 In Examples 1-4, a two-step method of "photochromic monomer synthesis-copolymerization" was used to graft photochromic groups (such as the spiropyran structure in SP-IMA) onto the polyacrylate backbone in the form of chemical bonds, forming a stable chemical bond. This bonding method can completely solve the compatibility problem between the photochromic component and the matrix, reduce pigment agglomeration and precipitation (the amount of pigment precipitation in the examples is only 0.20-0.31 mg / g, far lower than 5.62 mg / g in Comparative Example 1); at the same time, the chemical bond connection ensures that the photochromic groups are uniformly dispersed in the matrix, and can respond quickly to light (light response time 13-20s vs. 25s in Comparative Example 1), and is not easily detached after multiple cycles, thus exhibiting better fatigue resistance (absorbance retention rate 90.2%-92.4%).

[0043] Comparative Example 1 used a physical blending method, where 6-hydroxyspiropyran (SP-OH) was dispersed in the polymer matrix solely through mechanical stirring. The photochromic component and the matrix were only physically mixed, with no chemical interaction. In this method, SP-OH exhibits poor compatibility with polyacrylate and is prone to precipitation due to insufficient intermolecular forces. Furthermore, uneven dispersion leads to inconsistent response paths under light irradiation, resulting in prolonged light response time. Simultaneously, the pigment is easily lost during cycling, causing a rapid decrease in absorbance, and mechanical properties are reduced due to dispersion agglomeration.

[0044] Comparative Example 2 directly used unmodified 6-hydroxyspiropyran (SP-OH) in the copolymerization: SP-OH contains only hydroxyl groups and lacks carbon-carbon double bonds, making it unable to undergo free radical copolymerization with monomers such as MMA. It can only form weak hydrogen bonds with the matrix through hydroxyl groups. During the reaction, SP-OH gradually precipitates because it cannot be incorporated into the main chain, resulting in low and unevenly dispersed photochromic groups in the final material—manifested as an absorbance change value of only 0.35 (far lower than the 0.75-0.92 in the examples), a photoresponse time as long as 35s, and easy precipitation of pigment (4.87 mg / g). At the same time, the uncopolymerized SP-OH disrupts the continuity of the polymer matrix, leading to a significant decrease in mechanical properties.

[0045] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details.

Claims

1. A photochromic polyacrylate material, characterized in that, It is obtained by free radical copolymerization of the following raw material components in parts by weight: Photochromic monomer 2.5-10 parts; 6-24 parts of soft monomer; 9-36 parts of hard monomer; 3-12 parts of functional monomers; Initiator 0.07-0.28 parts; 30-120 parts of the first solvent; The photochromic monomer is obtained by reacting a photochromic compound containing hydroxyl groups with an acrylate monomer containing isocyanate groups in the presence of a catalyst.

2. The photochromic polyacrylate material according to claim 1, characterized in that, The raw materials for preparing the photochromic monomer include, by weight: 5-20 parts of a photochromic compound containing hydroxyl groups, 6-24 parts of an acrylate monomer containing isocyanate groups, 0.05-0.2 parts of a catalyst, and 25-100 parts of a second solvent.

3. The photochromic polyacrylate material according to claim 2, characterized in that, The photochromic compound containing hydroxyl groups is at least one of spiropyran compounds, spiroxazine compounds, or succinic anhydride compounds.

4. The photochromic polyacrylate material according to claim 2, characterized in that, The acrylate monomer containing the isocyanate group is at least one of ethyl isocyanate methacrylate or ethyl isocyanate acrylate.

5. The photochromic polyacrylate material according to claim 2, characterized in that, The catalyst is dibutyltin dilaurate, and the second solvent is toluene.

6. The photochromic polyacrylate material according to claim 2, characterized in that, The preparation method of photochromic monomer is as follows: add the photochromic compound containing hydroxyl groups to the second dissolution, stir to dissolve, then add the acrylate monomer containing isocyanate group and catalyst, react at 50-70℃ for 3-12h, after the reaction is completed, cool to room temperature, filter, and remove the solvent by rotary evaporation of the filtrate to obtain the photochromic monomer.

7. The photochromic polyacrylate material according to claim 1, characterized in that, The soft monomer includes one or more of ethyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, octadecyl acrylate, and ethoxyethoxyethyl acrylate. The hard monomers include one or more of methyl methacrylate, ethyl methacrylate, acrylonitrile, acryloylmorpholine, and N-vinylpyrrolidone; The functional monomers include one or more of 2-hydroxyethyl acrylate, hydroxybutyl acrylate, acrylamide, acrylic acid, and glycidyl acrylate; The initiator is one or both of azobisisobutyronitrile and azobisisoheptanenitrile.

8. A method for preparing a photochromic polyacrylate material as described in any one of claims 1-7, characterized in that, Includes the following steps: The soft monomer, hard monomer, functional monomer, and part of the first solvent are mixed and stirred under nitrogen at 50-70°C for at least 30 minutes. The first part of the initiator is added, and the reaction is carried out at 60-63°C for 1.5-6 hours. The second part of the initiator is added, and the reaction is continued for 1.5-6 hours. The temperature is raised to 65-68°C, and the remaining third part of the initiator is added. The reaction is carried out for 1.5-6 hours. After cooling, the remaining first solvent is added and mixed evenly to obtain the photochromic polyacrylate material.

9. A photochromic adhesive sheet, characterized in that, It is obtained by coating and curing a photochromic adhesive onto a substrate. The photochromic adhesive comprises the following raw material components by weight: 100 parts of the photochromic polyacrylate material as described in any one of claims 1-7, 0.03-0.12 parts of thermosetting agent, 0.015-0.06 parts of tackifier, and 0.015-0.06 parts of catalyst.

10. The photochromic adhesive sheet according to claim 9, characterized in that, It is prepared by the following method: Photochromic polyacrylate material, thermosetting agent, tackifier and catalyst are mixed evenly to obtain photochromic adhesive liquid; The photochromic adhesive is evenly coated on the surface of the substrate, dried, and then a release film is attached to the adhesive surface and cured to obtain the photochromic adhesive sheet.

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