Dimming film with functions of isolating ultraviolet and blocking water and oxygen and preparation method of dimming film

Abstract

The invention relates to the technical field of electronic light control products, and particularly discloses a light adjusting film with functions of isolating ultraviolet rays and blocking water and oxygen and a preparation method of the light adjusting film. According to the dimming film, the anti-ultraviolet EVA films are arranged on the two sides of the SPD color-changing film, and at least one anti-ultraviolet PET base material layer is arranged in the double-silver magnetron sputtering film, so that the indoor ultraviolet intensity can be reduced, and the influence of ultraviolet rays on human health can be reduced. Meanwhile, the double-silver magnetron sputtering film and the water vapor barrier film can also cooperate with the anti-ultraviolet EVA film to block water vapor, so that the possibility that the water vapor is in direct contact with the SPD color-changing film is reduced, the negative influence of the water vapor on the SPD color-changing film is reduced, and the dimming film can keep ideal electrochromism performance for a long time in a water vapor-rich environment.

Description

Technical Field

[0001] The present application relates to the technical field of electronic light control products, and more specifically, to a dimming film with the functions of isolating ultraviolet rays and blocking water and oxygen and a preparation method thereof. Background Art

[0002] The dimming film is a new type of electronic light control product, and an important branch of it is the electrically controlled dimming film. As the voltage applied to both ends changes, the electrically controlled dimming film switches between a transparent state with higher light transmittance and an opaque state with lower light transmittance. Due to the above properties, the electrically controlled dimming film can fully meet the dual requirements of indoor brightness adjustment and privacy protection.

[0003] Take the suspended particle dimming film as an example. The suspended particle dimming film is an important type of electrically controlled dimming film. The color-changing material of this dimming film is suspended particles dispersed in a polymer matrix in the form of micron-sized droplets. When the power is off, the suspended particles are randomly arranged by Brownian motion, which can absorb more than 99% of visible light, and the appearance of the dimming film appears opaque; when an electric field is applied, when a sufficient driving voltage is reached, the suspended particles will be arranged in order under the action of the electric field and allow light to pass through, and the dimming film will appear transparent. When the external electric field is removed, due to the interface anchoring effect between the suspended particle polymers, the arrangement and distribution of the liquid crystal droplets in the dimming film is disrupted, and the dimming film will return to an opaque state.

[0004] Regarding the above-mentioned related technologies, the inventors believe that, on the one hand, the dimming film in the prior art can only play a role in adjusting transparency and cannot prevent the transmission of ultraviolet rays. However, the dimming film is usually applied to automobile glass or building exterior walls. When the car is outdoors or the dimming film is applied to the facade of the building, the ultraviolet light in the environment will pass through the dimming film and enter the car or the building. Long-term exposure to ultraviolet rays will cause the temperature inside the car or indoors to be too high or cause damage to objects, and will also affect human health; on the other hand, the existing intelligent dynamic dimming film is greatly affected by water vapor in the use environment, which seriously affects the service life of the intelligent dynamic dimming film and limits the application scenarios of the intelligent dynamic dimming film; finally, the existing intelligent dynamic dimming film can only be used with laminated glass, which is inferior to the film in terms of cost and ease of application. Summary of the invention

[0005] In the related art, although the dimming film can adjust the transparency, it cannot effectively prevent the transmission of ultraviolet rays and is greatly affected by water vapor in the environment, making it difficult to apply. In order to improve this defect, the present application provides a dimming film with the function of isolating ultraviolet rays and blocking water and oxygen and a preparation method thereof.

[0006] In the first aspect, the present application provides a dimming film with the functions of blocking ultraviolet rays and water and oxygen, which adopts the following technical solution: A dimming film with the function of isolating ultraviolet rays and blocking water and oxygen, wherein the dimming film is sequentially stacked with a double silver magnetron sputtering film, an anti-ultraviolet EVA film, an SPD color-changing film, an anti-ultraviolet EVA film and a water vapor barrier film in the thickness direction; the double silver magnetron sputtering film comprises a first substrate layer and a second substrate layer, at least one of the first substrate layer and the second substrate layer is an anti-ultraviolet PET substrate layer; the anti-ultraviolet EVA film and the anti-ultraviolet PET substrate layer both contain an anti-ultraviolet agent; the water vapor barrier film comprises a water-blocking film substrate, one side of the water-blocking film substrate is covered with a pressed adhesive layer, and the other side is covered with a magnetron sputtering waterproof layer, and the magnetron sputtering waterproof layer is bonded to the anti-ultraviolet EVA film.

[0007] By adopting the above technical solution, the present application realizes the reflection of ultraviolet rays through the setting of double silver magnetron sputtering film, which can effectively reduce the transmittance of ultraviolet rays. At the same time, the present application also sets anti-ultraviolet EVA film on both sides of the SPD color-changing film, and sets at least one layer of anti-ultraviolet PET substrate layer in the double silver magnetron sputtering film, and stipulates that both the anti-ultraviolet EVA film and the anti-ultraviolet PET substrate layer contain anti-ultraviolet agent. Under the synergistic effect of the anti-ultraviolet substrate layer and the anti-ultraviolet EVA film, outdoor ultraviolet rays can be blocked and weakened by multiple layers when passing through the dimming film, thereby reducing the intensity of indoor ultraviolet rays, which helps to reduce the impact of ultraviolet rays on human health. At the same time, the double silver magnetron sputtering film and water vapor barrier film of the present application both use magnetron sputtering to achieve water vapor barrier, thereby reducing the impact of water vapor on the SPD color-changing film, and the anti-ultraviolet EVA film can also play a physical barrier role on the inner side of the double silver magnetron sputtering film and the water vapor barrier film, thereby further hindering the diffusion of water vapor near the SPD color-changing film, reducing the possibility of direct contact between water vapor and the SPD color-changing film, reducing the negative impact of water vapor on the SPD color-changing film, and enabling the dimming film to maintain ideal electrochromic performance for a long time in a water vapor-rich environment. In addition, due to the setting of the pressed adhesive layer, the dimming film of the present application can be directly attached to the existing glass surface to achieve the electrochromic transformation of the glass, without the need to replace it with a double-layer laminated dimming film, and can achieve the electrochromic effect at a lower cost.

[0008] Preferably, the anti-ultraviolet agent contains lignin structural units.

[0009] By adopting the above technical solution, the present application preferably selects the anti-ultraviolet agent to contain lignin structural units, which contain a large number of rigid benzene rings, ketone groups, phenolic hydroxyl groups, complex conjugated systems and a large number of hydrogen bonds. These structures and groups can respectively shield and absorb ultraviolet rays of different bands, and can produce good protection effects on ultraviolet rays of the entire band through synergistic effects, thereby giving the dimming film a good ultraviolet isolation function.

[0010] Preferably, the anti-ultraviolet agent comprises purified lignin, and the purified lignin is prepared according to the following method: industrial lignin and sodium hydroxide solution are mixed, and a lignin alkaline solution is obtained after stirring; insoluble impurities in the lignin alkaline solution are filtered out, and then the filtrate is acidified with hydrochloric acid to obtain a suspension; the suspension is washed to neutrality by centrifugal washing, and purified lignin is obtained after freeze-drying.

[0011] By adopting the above technical solution, the present application selects industrial lignin as raw material, firstly precipitates impurities in the industrial lignin by alkali dissolution, and the lignin components are separated in the form of alkali solution, and then the lignin is reprecipitated by acid precipitation, and after washing and drying, purified lignin with high purity and good anti-ultraviolet performance can be obtained. The purified lignin can also promote the crystallization of PET in the anti-ultraviolet PET substrate layer, and can make the anti-ultraviolet PET substrate layer have good water and oxygen barrier properties.

[0012] Preferably, the purified lignin is pretreated according to the following method before use: The purified lignin is added to anhydrous ethanol, and after constant temperature stirring, vacuum filtration is performed to separate the insoluble components from the soluble components. The insoluble components are washed with anhydrous ethanol, and the pretreatment of the purified lignin is completed after drying.

[0013] By adopting the above technical solution, the present application uses anhydrous ethanol to pretreat the purified lignin, and the anhydrous ethanol can dissolve the components with relatively low molecular weight in the purified lignin, and the remaining precipitate is composed of purified lignin with relatively high molecular weight. After the above pretreatment, the molecular weight of the purified lignin increases, which can have a better blocking effect on ultraviolet rays, and help improve the anti-ultraviolet performance of the dimming film.

[0014] Preferably, the content of the purified lignin in the UV-resistant PET substrate layer is 2.5-3.5 wt %.

[0015] By adopting the above technical solution, the present application limits the content of purified lignin in the UV-resistant PET substrate layer, which helps to improve the UV protection performance of the dimming film.

[0016] Preferably, the content of the purified lignin in the UV-resistant EVA film is 3-5wt%.

[0017] By adopting the above technical solution, the present application limits the content of purified lignin in the anti-ultraviolet PET layer, which helps to improve the anti-ultraviolet performance of the dimming film.

[0018] Preferably, the anti-ultraviolet agent further comprises modified titanium dioxide, wherein the modified titanium dioxide is titanium dioxide particles with sulfonated lignin adsorbed on the surface.

[0019] By adopting the above technical solution, the present application selects modified titanium dioxide as the second component in the anti-ultraviolet agent, and the sulfonated lignin can be adsorbed on the surface of titanium dioxide by means of the sulfonic acid group, which promotes the uniform dispersion of the modified titanium dioxide. In addition to being able to play the ultraviolet shielding role of titanium dioxide itself, the modified titanium dioxide can also absorb and shield ultraviolet rays through the sulfonated lignin group on the surface, and can produce a good synergistic effect with the purified lignin, which helps to improve the anti-ultraviolet performance of the dimming film.

[0020] Preferably, the modified titanium dioxide is prepared according to the following method: (1) adding sulfonated lignin into distilled water to dissolve it, thereby obtaining a sulfonated lignin solution; adding tetrabutyl titanate into ethanol to disperse it, thereby obtaining a titanate solution; (2) The titanate solution and the sulfonated lignin solution are mixed, and the product is dried after a hydrothermal reaction to obtain modified titanium dioxide.

[0021] By adopting the above technical scheme, the present application first prepares a sulfonated lignin solution, and then carries out a hydrothermal reaction using tetrabutyl titanate as a titanium source. During the reaction, the sulfonated lignin is adsorbed on the surface of titanium dioxide by electrostatic adsorption and covalent bonding, and the agglomeration of titanium dioxide is reduced, thereby obtaining modified titanium dioxide with good dispersion effect.

[0022] Preferably, the sulfonated lignin is prepared according to the following method: Industrial lignin and sodium hydroxide solution are mixed and stirred to obtain a lignin alkaline solution, formaldehyde is added to the lignin alkaline solution, sodium sulfite is added after stirring and heating, the temperature is continued to be raised, stirred and heated, and then dialyzed to remove inorganic salts in the reaction system, and then the solvent is removed by rotary evaporation to obtain sulfonated lignin.

[0023] By adopting the above technical scheme, the present application uses industrial lignin as raw material and sodium sulfite as sulfonating agent, and replaces the phenolic hydroxyl and methoxy groups in the lignin with sulfonic acid groups through a sulfomethylation reaction, thereby obtaining sulfonated lignin.

[0024] In a second aspect, the present application provides a method for preparing a dimming film having the functions of isolating ultraviolet rays and blocking water and oxygen, which adopts the following technical solution.

[0025] A method for preparing a dimming film having the functions of isolating ultraviolet light and blocking water and oxygen, comprising the following steps: (1) coating a mounting glue on the surface of the first substrate layer, laminating a layer of release film on the surface of the mounting glue, thermally curing the mounting glue to form a wear-resistant outer layer, then removing the release film, sequentially sputtering titanium pentoxide, aluminum-doped zinc oxide, silver, nickel, titanium pentoxide, aluminum-doped zinc oxide, silver, nickel, and titanium pentoxide on the surface of the first substrate layer to obtain an energy-saving functional layer, coating a pressure-sensitive glue on the surface of the energy-saving functional layer, laminating a second substrate layer on the surface of the pressure-sensitive glue, and coating another layer of pressure-sensitive glue on the surface of the second substrate layer to obtain a double silver magnetron sputtering film for standby use; magnetron sputtering is performed on one side of the water-blocking film substrate to form a magnetron sputtering waterproof layer, and a layer of pressure-sensitive glue is coated on the other side of the water-blocking film substrate to form a pressure-sensitive adhesive layer to obtain a water vapor barrier film for standby use; (2) The SPD color-changing film is sandwiched between two pieces of anti-ultraviolet EVA films, and then one piece of anti-ultraviolet EVA film is laminated to the side of the double silver magnetron sputtering film with the pressure-sensitive adhesive, and the other piece of anti-ultraviolet EVA film is laminated to the side of the water vapor barrier film with the magnetron sputtering waterproof layer. After hot pressing treatment, a dimming film with the functions of isolating ultraviolet rays and blocking water and oxygen is obtained.

[0026] By adopting the above technical scheme, the present application first prepared a double silver magnetron sputtering film and a water vapor barrier film respectively, and then assembled the double silver magnetron sputtering film, anti-ultraviolet EVA film, SPD color-changing film and water vapor barrier film, and combined the layers into one through hot pressing treatment to obtain a dimming film with the function of isolating ultraviolet rays and blocking water and oxygen.

[0027] In summary, this application has the following beneficial effects: 1. The dimming film of the present application is provided with anti-ultraviolet EVA films on both sides of the SPD color-changing film, and at least one layer of anti-ultraviolet PET substrate layer is provided in the double silver magnetron sputtering film, which can reduce the intensity of indoor ultraviolet rays and help reduce the impact of ultraviolet rays on human health. At the same time, the double silver magnetron sputtering film and the water vapor barrier film can also cooperate with the anti-ultraviolet EVA film to block water vapor, reducing the possibility of direct contact between water vapor and the SPD color-changing film, reducing the negative impact of water vapor on the SPD color-changing film, and enabling the dimming film to maintain ideal electrochromic performance for a long time in an environment rich in water vapor.

[0028] 2. The dimming film of the present application can be directly attached to the existing glass surface without the need to replace it with a double-layer laminated dimming film, and the electrochromic transformation of the glass can be achieved at a lower cost.

[0029] 3. This application uses purified lignin and modified titanium dioxide as anti-ultraviolet agents, which can fully absorb and shield ultraviolet rays, giving the dimming film a good ultraviolet isolation function. DETAILED DESCRIPTION

[0030] The present application is further described in detail below in conjunction with embodiments, preparation examples and comparative examples. The raw materials involved in the present application can all be obtained commercially.

[0031] Preparation example of purified lignin The following is an explanation using Preparation Example 1.

[0032] Preparation Example 1 In this preparation example, purified lignin was prepared according to the following method: Industrial lignin (sulfate lignin) and 0.001 mol / L sodium hydroxide solution are mixed in a weight ratio of 1:25, and a lignin alkaline solution is obtained after stirring at 25°C; insoluble impurities in the lignin alkaline solution are filtered out, and then the pH of the filtrate is adjusted to 2 with 10wt% hydrochloric acid to obtain a suspension; the suspension is washed to neutrality by centrifugal washing, and then purified lignin is obtained after freeze-drying.

[0033] Preparation example of modified titanium dioxide The following is an explanation using Preparation Example 1.

[0034] Preparation Example 1 The sulfonated lignin of this preparation example was prepared according to the following method: 5 g of industrial lignin was mixed with 100 mL of sodium hydroxide solution (pH = 10.5), and stirred for 30 min to obtain a lignin alkaline solution. 1 mL of formaldehyde was added to the lignin alkaline solution, and the solution was stirred and heated at 70 ° C for 2 h, and then 3.5 g of sodium sulfite was added. The temperature was continued to rise to 90 ° C, and the solution was stirred and heated for 5 h. The inorganic salts in the reaction system were removed by dialyzing, and then the solvent was removed by rotary evaporation to obtain sulfonated lignin.

[0035] This preparation example provides a modified titanium dioxide, which is prepared according to the following method: (1) 3 g of sulfonated lignin was added to 50 mL of distilled water to dissolve to obtain a sulfonated lignin solution; 4 g of tetrabutyl titanate was added to 20 mL of ethanol to disperse to obtain a titanate solution; (2) The titanate solution and the sulfonated lignin solution are mixed, subjected to a hydrothermal reaction at 130° C. for 8 h, and then the product is dried at 50° C. to obtain modified titanium dioxide. Example

[0036] The following description is given by taking Example 1 as an example.

[0037] Example 1 The present embodiment provides a dimming film with the functions of isolating ultraviolet rays and blocking water and oxygen. The dimming film is sequentially stacked with a 125 μm thick double silver magnetron sputtering film, a 400 μm thick anti-ultraviolet EVA film, a 200 μm thick SPD color-changing film, a 400 μm thick anti-ultraviolet EVA film and a 125 μm thick water vapor barrier film in the thickness direction; the double silver magnetron sputtering film includes a first substrate layer and a second substrate layer, wherein the first substrate layer is a PET substrate layer, and the second substrate layer is an anti-ultraviolet PET substrate layer; the anti-ultraviolet EVA film and the anti-ultraviolet PET The substrate layer contains an anti-ultraviolet agent, and the anti-ultraviolet agent is the purified lignin of Preparation Example 1. The content of the purified lignin in the anti-ultraviolet PET substrate layer is 2wt%, and the content in the anti-ultraviolet EVA film is 2.5wt%; the water vapor barrier film includes a water-blocking film substrate of PET material, one side of the water-blocking film substrate is covered with a pressed adhesive layer, and the other side is covered with a 100nm thick magnetron sputtering waterproof layer, the magnetron sputtering waterproof layer is composed of aluminum oxide and zinc oxide, wherein the molar ratio of aluminum to zinc is 3:1, and the magnetron sputtering waterproof layer is bonded to the anti-ultraviolet EVA film.

[0038] This embodiment provides a method for preparing a dimming film having the functions of blocking ultraviolet rays and water and oxygen, comprising the following steps: (1) coating a mounting glue (polyurethane mounting glue) on the surface of the first substrate layer, laminating a release film on the surface of the mounting glue, the mounting glue is thermally cured to form a wear-resistant outer layer, then removing the release film, sputtering 60nm thick titanium pentoxide, 30nm thick aluminum-doped zinc oxide, 20nm thick silver, 10nm thick nickel, 75nm thick titanium pentoxide, 30nm thick aluminum-doped zinc oxide, 20nm thick silver, 10nm thick nickel, and 60nm thick titanium pentoxide on the surface of the first substrate layer in sequence to obtain an energy-saving functional layer, coating a pressure-sensitive glue on the surface of the energy-saving functional layer, laminating a second substrate layer on the surface of the pressure-sensitive glue, and coating another layer of pressure-sensitive glue on the surface of the second substrate layer to obtain a double silver magnetron sputtering film for standby use; performing magnetron sputtering on one side of the water-blocking film substrate to form a magnetron sputtering waterproof layer, coating a layer of pressure-sensitive glue on the other side of the water-blocking film substrate to form a pressure-sensitive adhesive layer, and obtaining a water vapor barrier film for standby use; (2) The SPD color-changing film is sandwiched between two pieces of anti-ultraviolet EVA films, and then one piece of anti-ultraviolet EVA film is laminated to the side of the double silver magnetron sputtering film with the pressure-sensitive adhesive, and the other piece of anti-ultraviolet EVA film is laminated to the side of the water vapor barrier film with the magnetron sputtering waterproof layer, and a release film is covered on the surface of the laminated adhesive layer, and the film is preheated at 50°C for 80 minutes in a hot pressing device, and then heated at 100°C for 120 minutes. After cooling, the release film is torn off to obtain a dimming film with UV and water and oxygen blocking functions.

[0039] Example 2 The difference between this embodiment and embodiment 1 is that the first substrate layer is replaced with an anti-ultraviolet PET substrate layer which is the same as the second substrate layer.

[0040] Example 3 The difference between this embodiment and embodiment 1 is that the purified lignin is pretreated according to the following method before use: The purified lignin was added to anhydrous ethanol at a solid-liquid ratio of 1:20, and the mixture was stirred at a constant temperature of 300 rpm at 25°C for 2 hours, and then vacuum filtered to separate the insoluble components from the soluble components. The insoluble components were washed with anhydrous ethanol, and the pretreatment of the purified lignin was completed after drying.

[0041] As shown in Table 1, the difference between Examples 3-6 is that the content of purified lignin in the UV-resistant PET substrate layer (referred to as the first proportion of purified lignin) is different.

[0042] Table 1 The first proportion of purified lignin sample Purified lignin first proportion / wt% Example 3 2 Example 4 2.5 Example 5 3 Example 6 3.5 As shown in Table 2, the difference between Examples 6-9 is that the content of purified lignin in the anti-ultraviolet EVA film (referred to as the second proportion of purified lignin) is different.

[0043] Table 2 The second proportion of purified lignin sample Purified lignin second proportion / wt% Example 6 2.5 Example 7 3 Example 8 4 Example 9 5 Example 10 The difference between this embodiment and embodiment 9 is that the anti-ultraviolet agent further includes nano titanium dioxide (average particle size 35 nm), and the content of nano titanium dioxide in the anti-ultraviolet PET substrate layer and the EVA film is 1.5 wt %.

[0044] Embodiment 11 The difference between this embodiment and embodiment 10 is that the nano titanium dioxide is replaced by the same weight of modified titanium dioxide, and the modified titanium dioxide is prepared according to the method of preparation example 2.

[0045] Comparative Example Comparative Example 1 The difference between this comparative example and Example 1 is that the anti-ultraviolet agent in the anti-ultraviolet PET substrate layer and the anti-ultraviolet EVA film is removed.

[0046] Comparative Example 2 The difference between this comparative example and Example 1 is that the anti-UV EVA film is removed, and the double silver magnetron sputtering film and the water vapor barrier film are directly bonded to the front and back sides of the SPD color-changing film, wherein the magnetron sputtering waterproof layer of the water vapor barrier film is bonded to the SPD color-changing film by a pressure-sensitive adhesive.

[0047] Comparative Example 3 The difference between this comparative example and Example 1 is that the double silver magnetron sputtering film and the water vapor barrier film are removed.

[0048] Performance testing methods 1. Water barrier performance The encapsulated dimming films of each embodiment and comparative example are placed in a constant temperature and humidity test box for wet heat treatment, and the test conditions are 85°C, 85% humidity, and 1000 hours. After the wet heat treatment, an AC voltage of 110V is applied to both ends of the dimming film, and the visible light transmittance of the dimming film after wet heat treatment is detected with reference to the record of "GB / T 2680-2021" (the maximum value in a complete light-dark cycle is selected), and the haze of the dimming film after wet heat treatment is detected with reference to the record of "GB / T 2410-2008" (the minimum value in a complete light-dark cycle is selected), and then the visible light transmittance and haze of comparative example 1 are used as the benchmark to calculate the ratio between the visible light transmittance and haze of each embodiment and comparative example and the result of comparative example 1, and the results are recorded as relative transmittance and relative haze. The results are shown in Table 3.

[0049] 2. Oxygen barrier performance According to the record of GB / T1038-2000, the oxygen permeability of the dimming film under standard atmospheric pressure was tested. The test temperature was 25°C, the test pressure was 0.1MPa, the relative humidity was 75%, the gas atmosphere was oxygen, and the test time was 24h. After the test was completed, the oxygen permeability of Comparative Example 1 was used as a benchmark to calculate the ratio between the oxygen permeability of each embodiment and the comparative example and the oxygen permeability of Comparative Example 1, and the ratio was recorded as the oxygen relative permeability. The results are shown in Table 3.

[0050] 3. UV reduction performance The ultraviolet blocking rate of the dimming film was tested using Linshang optical transmittance meter LS183. After the test, the ultraviolet blocking rate of comparative example 1 was used as a benchmark to calculate the ratio between the ultraviolet blocking rate of each embodiment and comparative example and the ultraviolet blocking rate of comparative example 1. The ratio was recorded as the relative ultraviolet blocking rate. The results are shown in Table 3.

[0051] Table 3 Test results Combining Example 1 and Comparative Example 1 with Table 3, it can be seen that Example 1 has a higher relative transmittance and relative haze after wet heat treatment, indicating that the electrochromic performance is less affected by water vapor and has better water resistance. By comparing the relative oxygen transmission rate, it can be seen that the oxygen barrier performance of Example 1 is also good. This is because the addition of purified lignin improves the crystallinity of PET. The relative UV barrier material of Example 1 is significantly higher than that of Comparative Example 1, indicating that the lack of anti-UV agent will affect the anti-UV performance of the dimming film.

[0052] Combining Example 1 and Comparative Example 2 with Table 3, it can be seen that the relative transmittance of Comparative Example 2 is significantly lower than that of Comparative Example 1, while the relative haze and relative oxygen transmission rate are significantly higher than those of Comparative Example 1, indicating that in the absence of an anti-ultraviolet EVA film, the oxygen barrier performance and water barrier performance of the dimming film are greatly affected. The relative UV blocking rate of Example 1 is significantly higher than that of Comparative Example 1, indicating that the double silver magnetron sputtering film alone cannot fully achieve a good anti-ultraviolet effect.

[0053] It can be seen from Example 1 and Comparative Example 3 and Table 3 that in the absence of a double silver magnetron sputtering film and a water vapor barrier film, it is difficult to fully improve the water barrier, oxygen barrier and UV resistance effects by only relying on the anti-UV EVA film.

[0054] It can be seen from Example 1 and Example 2 and Table 3 that when the first substrate layer also contains purified lignin, the lignin promotes the crystallization of PET, so the crystallinity of PET is improved, thereby fully improving the water-blocking, oxygen-blocking and UV-resistant effects of the dimming film.

[0055] Combining Example 2 and Example 3 with Table 3, it can be seen that the relative UV blocking rate measured in Example 3 is significantly improved, indicating that the purified lignin after pretreatment can more effectively improve the anti-ultraviolet performance of the dimming film. At the same time, the pretreatment of purified lignin also improves the water and oxygen barrier properties of the dimming film to a certain extent.

[0056] It can be seen from Examples 3-6, 6-9 and Table 3 that when the content of purified lignin in the anti-ultraviolet PET substrate layer is 2.5-3.5wt%, the dimming film has good oxygen barrier, water barrier and anti-ultraviolet performance. When the content of purified lignin in the anti-ultraviolet EVA film is 3-5wt%, the dimming film has good anti-ultraviolet performance.

[0057] It can be seen from Example 9, Examples 10-11 and Table 3 that the addition of nano titanium dioxide and modified titanium dioxide can improve the anti-ultraviolet performance, among which the effect of modified titanium dioxide is more obvious. This is because the modified titanium dioxide has a better dispersion effect, and in addition to the ultraviolet shielding effect of titanium dioxide, the modified titanium dioxide can also absorb and shield ultraviolet rays through the sulfonated lignin groups on the surface, and can produce good synergistic effects with purified lignin, which helps to improve the anti-ultraviolet performance of the dimming film.

[0058] The above embodiments are merely explanations of the present application and are not limitations of the present application. After reading this specification, those skilled in the art may make modifications to the embodiments of the present application without any creative contribution as needed. However, as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A dimming film with UV and water / oxygen blocking functions, characterized in that: The dimming film is stacked in sequence along the thickness direction with a double silver magnetron sputtering film, an anti-ultraviolet EVA film, an SPD color-changing film, an anti-ultraviolet EVA film and a water vapor barrier film; the double silver magnetron sputtering film includes a first substrate layer and a second substrate layer, at least one of the first substrate layer and the second substrate layer is an anti-ultraviolet PET substrate layer; the anti-ultraviolet EVA film and the anti-ultraviolet PET substrate layer both contain an anti-ultraviolet agent; the water vapor barrier film includes a water-blocking film substrate, one side of the water-blocking film substrate is covered with a pressed adhesive layer, and the other side is covered with a magnetron sputtering waterproof layer, and the magnetron sputtering waterproof layer is bonded to the anti-ultraviolet EVA film.

2. The dimming film with UV and water / oxygen blocking functions according to claim 1, characterized in that: The anti-ultraviolet agent contains lignin structural units.

3. The dimming film with UV and water / oxygen blocking functions according to claim 2, characterized in that: The anti-ultraviolet agent comprises purified lignin, and the purified lignin is prepared according to the following method: Industrial lignin and sodium hydroxide solution are mixed and stirred to obtain a lignin alkali solution; insoluble impurities in the lignin alkali solution are removed by filtration, and then the filtrate is acidified with hydrochloric acid to obtain a suspension; The suspension was washed to neutrality by centrifugal washing, and purified lignin was obtained after freeze-drying.

4. The dimming film with UV and water / oxygen blocking functions according to claim 3, characterized in that: The purified lignin was pretreated as follows before use: The purified lignin is added to anhydrous ethanol, and after constant temperature stirring, vacuum filtration is performed to separate the insoluble components from the soluble components. The insoluble components are washed with anhydrous ethanol, and the pretreatment of the purified lignin is completed after drying.

5. The dimming film with UV and water / oxygen blocking functions according to claim 3, characterized in that: The content of the purified lignin in the UV-resistant PET substrate layer is 2.5-3.5 wt %.

6. The dimming film with UV and water / oxygen blocking functions according to claim 3, characterized in that: The content of the purified lignin in the anti-ultraviolet EVA film is 3-5wt%.

7. The dimming film with UV and water / oxygen blocking functions according to claim 1, characterized in that: The anti-ultraviolet agent also includes modified titanium dioxide, which is titanium dioxide particles with sulfonated lignin adsorbed on the surface.

8. The dimming film with UV and water / oxygen blocking functions according to claim 7, characterized in that: The modified titanium dioxide is prepared according to the following method: (1) adding sulfonated lignin to distilled water to dissolve it, thereby obtaining a sulfonated lignin solution; adding tetrabutyl titanate to ethanol to disperse it, thereby obtaining a titanate solution; (2) The titanate solution and the sulfonated lignin solution are mixed, and the product is dried after a hydrothermal reaction to obtain modified titanium dioxide.

9. The dimming film with UV and water / oxygen blocking functions according to claim 8, characterized in that: The sulfonated lignin is prepared according to the following method: Industrial lignin and sodium hydroxide solution are mixed and stirred to obtain a lignin alkaline solution, formaldehyde is added to the lignin alkaline solution, sodium sulfite is added after stirring and heating, the temperature is continued to be raised, stirred and heated, and then dialyzed to remove inorganic salts in the reaction system, and then the solvent is removed by rotary evaporation to obtain sulfonated lignin.

10. The method for preparing a dimming film having the functions of blocking ultraviolet light and water and oxygen according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) Coating a mounting glue on the surface of the first substrate layer, laminating a release film on the surface of the mounting glue, thermally curing the mounting glue to form a wear-resistant outer layer, then removing the release film, sputtering titanium pentoxide, aluminum-doped zinc oxide, silver, nickel, titanium pentoxide, aluminum-doped zinc oxide, silver, nickel, and titanium pentoxide on the surface of the first substrate layer in sequence to obtain an energy-saving functional layer, coating a pressure-sensitive adhesive on the surface of the energy-saving functional layer, laminating a second substrate layer on the surface of the pressure-sensitive adhesive, and coating another layer of pressure-sensitive adhesive on the surface of the second substrate layer to obtain a double silver magnetron sputtering film for standby use; magnetron sputtering is performed on one side of the water-blocking film substrate to form a magnetron sputtering waterproof layer, and a layer of pressure-sensitive adhesive is coated on the other side of the water-blocking film substrate to form a pressure-sensitive adhesive layer to obtain a water vapor barrier film for standby use; (2) The SPD color-changing film is sandwiched between two pieces of UV-resistant EVA films, and then one piece of UV-resistant EVA film is laminated to the side of the double silver magnetron sputtering film with the pressure-sensitive adhesive, and the other piece of UV-resistant EVA film is laminated to the side of the water vapor barrier film with the magnetron sputtering waterproof layer. After hot pressing treatment, a dimming film with UV and water and oxygen blocking functions is obtained.

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