Dicarbonyl acrylate copolymer for light valve and light valve

Abstract

The present invention provides a dicarbonyl acrylate copolymer for a light valve and a light valve. By introducing an acrylate monomer containing an oxygen-α, β-dicarbonyl functional group structure, a macromolecular copolymer is prepared by a heating polymerization method to form a suspension medium with an oxygen-α, β-dicarbonyl functional group structure, thereby improving the anti-aging and anti-degradation properties of the light valve material, thereby improving the thermal stability of the light valve and dimming glass components, extending their service life, and meeting actual use requirements.

Description

Technical Field

[0001] The invention relates to the field of electronic light-controlling materials, and in particular to an acrylate copolymer for a light valve, the light valve and a dimming glass component with thermal stability. Background Art

[0002] A light valve is an electronic light control device. It is mainly composed of a light control layer between two transparent conductive films. When the electric field is turned on, the arrangement or state of the material in the light control layer changes, thereby changing the light transmittance of the device, such as from low transmittance to high transmittance, or from high transmittance to low transmittance. Through the action of the electric field, it can achieve rapid conversion between the on state and the off state. According to the different light control mechanisms of the light control layer, light valves can be divided into suspended particle light valves, polymer dispersed liquid crystal light valves, electrochemical reaction light valves, etc.

[0003] Depending on the substrate of the light valve, the light valve can be based on a plastic sheet such as PET, which is generally called a dimming film; or it can be based on glass, which is generally called a dimming glass. The assembly formed by laminating the dimming film is generally called a dimming glass assembly.

[0004] Smart film, smart glass and smart glass components need to withstand high-temperature pressing during the preparation process, and must withstand the long-term test of ambient temperature during actual use. All of these put forward requirements for the heat resistance and stability of the products.

[0005] The inventor of this patent provides a method for preparing a suspended particle light valve, and creatively introduces a specific type of acrylate monomer with an oxygen-α, β dicarbonyl functional group structure, and prepares a specific type of macromolecular copolymer containing an oxygen-α, β dicarbonyl functional group structure by means of heating polymerization, forming a suspension medium with its unique structure for preparing a suspended particle dimming film. The oxygen-α, β dicarbonyl functional group structure can produce a chelating effect with the metal ions in the suspended particles, stabilize the suspended particles, prevent the particles from agglomerating and decomposing under heat, and at the same time, the oxygen-α, β dicarbonyl functional group also has the activity of capturing I2 molecules, and can form CI bonds, thereby achieving the effect of improving the overall thermal stability of the dimming film, extending the service life of the light valve and the light valve assembly, and meeting the actual use requirements. Summary of the invention

[0006] On the basis of proposing a light valve and a light valve preparation method, the inventor further improved the polymer composition of the suspension medium to enhance its thermal stability.

[0007] In a first aspect of the present invention, there is provided an acrylate copolymer for a light valve, wherein the acrylate copolymer contains oxygen-α, β dicarbonyl functional groups and has a structure as shown in formula (A).

[0008]

[0009] Y1 and Y2 are independently selected from one of H and CH3.

[0010] Furthermore, the acrylic ester copolymer is obtained by copolymerizing the following monomers under the action of a copolymerization catalyst:

[0011] (a) acrylate monomers,

[0012] (b) an acrylate unsaturated monomer having oxygen-α, β dicarbonyl functional groups, the structure of which is shown in formula (B),

[0013]

[0014] X is an alkyl or cycloalkyl group having 1 to 8 carbon atoms;

[0015] R, Y1, and Y2 are independently selected from one of H and CH3.

[0016] Furthermore, the (a) acrylic acid ester monomer is at least one of an acrylic acid alkyl ester monomer or an acrylic acid hydroxy ester monomer.

[0017] Furthermore, the (a) is an alkyl acrylate monomer, the general formula is

[0018] CH2=CR1COO-R1' Formula (C)

[0019] Wherein, R1 is CH3 or H; R1' is C n H 2n+1 , n is an integer from 1 to 18.

[0020] Furthermore, the (a) is a hydroxy acrylate monomer, the general formula is

[0021] CH2=CR2COO-R2' Formula (D)

[0022] Wherein, R2 is CH3 or H; R2' is C q H 2q -OH, q is an integer of 1-8.

[0023] Furthermore, the ratio between the monomers (a) and (b) forming the acrylic ester copolymer is, based on the total mass being 100 parts, 50 to 95 parts by mass of the monomer (a) and 5 to 50 parts by mass of the monomer (b).

[0024] Furthermore, the copolymerization catalyst is a thermally initiated free radical catalyst, preferably at least one of an azo initiator, tributyltin hydride (n-Bu3SnH) / AIBN, ammonium persulfate, and an organic peroxide.

[0025] Furthermore, the azo initiator is selected from at least one of azobisisobutyronitrile (AIBN), azobisisoheptanenitrile (ABVN), dimethyl azobisisobutyrate (AIBME), azobisisobutylamidine hydrochloride (AIBA), and azobisisobutylimidazoline hydrochloride (AIBI).

[0026] Furthermore, the peak molecular weight of the acrylic ester copolymer is 1,000 to 10,000.

[0027] A second aspect of the present invention provides a light valve, comprising:

[0028] a first transparent substrate,

[0029] a first transparent electrode formed on a first transparent substrate,

[0030] The second transparent substrate,

[0031] a second transparent electrode formed on a second transparent substrate,

[0032] The first transparent electrode and the second transparent electrode are arranged opposite to each other, and

[0033] A light-controlling layer is arranged between the first transparent electrode and the second transparent electrode; the light-controlling layer comprises a polymer matrix; droplets of a suspension medium are dispersed in the polymer matrix, solid light-controlling particles are distributed in the droplets of the suspension medium, and the suspension medium contains the above-mentioned acrylic ester copolymer having oxygen-α, β dicarbonyl functional groups.

[0034] Furthermore, the suspension medium also includes a non-conductive liquid; the non-conductive liquid is selected from at least one of fluorocarbon organic compounds, phthalates, trimellitic acid esters, dodecylbenzene, polybutene oil, epoxidized soybean oil and epoxidized linseed oil.

[0035] Furthermore, the solid light-controlling particles are selected from one or more of oxide nanorods, perovskite nanorods and polyiodine compound nanorods; the particle length of the solid light-controlling particles is 50 to 800 nm; and the particle aspect ratio of the solid light-controlling particles is 2 to 30.

[0036] Furthermore, the mass ratio of the total mass of the suspension medium and the solid light-controlling particles to the polymer matrix is ​​1:(1-10); the mass ratio of the acrylic ester copolymer in the suspension medium to the total mass of the suspension medium is 1:(1-5); the mass ratio of the suspension medium to the solid light-controlling particles is 1:(0.05-0.2).

[0037] Furthermore, the polymer matrix is ​​a solid siloxane polymer.

[0038] Furthermore, the polymer matrix is ​​formed by cross-linking and curing an organic silicone oil polymer matrix precursor having unsaturated bonds.

[0039] Further, a photoinitiator is added to the polymer matrix precursor to induce polymerization reaction by irradiation. The photoinitiator can be those commonly used in the art, for example, it can be selected from 184 (CAS No. 947-19-3), ITX (CAS No. 5495-84-1 or 83846-86-0), 819 (CAS No. 162881-26-7), 1173 (CAS No. 7473-98-5), BDK (CAS No. 24650-42-8), BP (CAS No. 119-61-9), TPO (CAS No. 75980-60-8), 369 (CAS No. 119313-12-1), 907 (CAS No. 71868-10-5), including any one thereof or any combination thereof.

[0040] Furthermore, the first transparent substrate and the second transparent substrate are glass plates and / or transparent plastic sheets.

[0041] Furthermore, the first transparent electrode and the second transparent electrode are each independently selected from at least one of an ITO conductive layer, a FZO conductive layer, an IZO conductive layer, a GZO conductive layer, an AZO conductive layer, a PEDOT conductive layer, a nano-Ag wire conductive layer, conductive graphene and a nano-Cu wire conductive layer.

[0042] Furthermore, the first transparent electrode and / or the second transparent electrode is covered with an adhesive layer, and the adhesive layer material includes at least one of epoxy resin, polyurethane resin, polyimide resin, polystyrene resin, acrylic resin, modified acrylic resin and silicone resin.

[0043] In a third aspect of the present invention, a dimming glass assembly with excellent thermal stability is provided, comprising a first glass plate and a second glass plate, and a light valve having the above-mentioned acrylic ester copolymer suspension medium containing oxygen-α, β dicarbonyl functional groups arranged between the first glass plate and the second glass plate.

[0044] Further, a first interlayer is provided between the first glass plate and the light valve, and / or a second interlayer is provided between the second glass plate and the light valve.

[0045] In the present invention, there is no special restriction on the types of the first glass plate and the second glass plate. They can be transparent glass used in conventional dimming glass assemblies well known to those skilled in the art. They can be ordinary glass such as inorganic glass and organic glass, or functional glass such as UV blocking glass, IR blocking glass, Low-E glass, tempered glass or antibacterial glass, etc. They can also be selected from colored glass such as gray glass and brown glass.

[0046] In the present invention, there is no special restriction on the types of the first interlayer and the second interlayer, which are conventional interlayers for dimming glass components well known to those skilled in the art, and may be EVA films, TPU films, PVB films, or functional films, such as UV-blocking EVA films, UV-blocking TPU films, UV-blocking PVB films, etc., or films with certain colors, such as gray EVA films, gray TPU films, gray PVB films, etc.

[0047] In the present invention, the method for manufacturing the dimming glass assembly is not particularly limited, and can be a conventional laminating method of the dimming glass assembly in the art, such as laminating in a laminator, or laminating in an autoclave or a laminating box / furnace.

[0048] The suspension medium of the light valve in the present invention is obtained from at least one acrylic ester copolymer, wherein the acrylic ester copolymer contains a unit (b) of an acrylic ester monomer having an oxygen-α, β dicarbonyl functional group structure, which can react with the metal ion Me in the light-controlling particle. n+ To form a stable chelate, as shown in formula (E),

[0049]

[0050] R, Y1, and Y2 are independently selected from one of H and CH3.

[0051] Compared with the acrylate copolymer without unit (b), the acrylate copolymer containing unit (b) with oxygen-α, β dicarbonyl functional group structure has significantly improved test performance in the thermal aging stability experiment. At the same time, the introduction of the (b) monomer with oxygen-α, β dicarbonyl functional group to participate in the polymerization reaction to generate a high thermal stability suspension medium is conducive to the physical distribution state and chemical stability state of the light-controlling particles. It plays a role in inhibiting polymerization and resisting decomposition, and ultimately significantly improves the working stability of the light valve and light valve assembly under the conditions of thermal aging test, prolongs the service life of dimming glass, and meets a wide range of application needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. The drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without creative work.

[0053] Figure 1A schematic diagram of the structure of a dimming film provided by an embodiment of the present invention, wherein 1 is a transparent electrode, 2 is a light-controlling layer, 3 is a transparent substrate, 21 is a polymer matrix, 22 is a suspension medium droplet containing solid light-controlling particles, and 23 is a solid light-controlling particle.

[0054] Figure 2 This is the GPC test result of the acrylic ester copolymer prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0055] the term

[0056] In the present invention, the following terms used have the meanings defined below.

[0057] Light valve:

[0058] A light valve is an electronic light control device, which mainly consists of a light control layer arranged between two layers of transparent conductive films. When the electric field is turned on, the arrangement or state of the material in the light control layer changes, thereby changing the light transmittance characteristics of the device, such as changing from low transmittance to high transmittance, or from high transmittance to low transmittance.

[0059] Oxygen-α, β-dicarbonyl functional groups:

[0060] The oxygen-α, β-dicarbonyl functional group has a structure as shown in formula (A),

[0061]

[0062] Y1 and Y2 are independently selected from one of H and CH3.

[0063] In the present invention, the suspension medium is sometimes also referred to as a liquid suspension medium.

[0064] The suspension medium in the present invention is composed of at least one acrylic ester copolymer. When the suspension medium is composed of only one acrylic ester copolymer, the two terms acrylic ester copolymer and suspension medium are equivalent.

[0065] The present invention provides a light valve that can significantly improve its thermal stability. By using an acrylate monomer having an oxygen-α, β dicarbonyl functional group structure and then heating and polymerizing to form an acrylate copolymer, the suspension medium containing the acrylate copolymer can effectively solve the problem of poor thermal stability of the dimming film. In particular, the present invention can effectively achieve improvement in the thermal stability of the light valve relative to the material without the unit (b) by using a unit (b) having the following structural formula (B), that is, an acrylate monomer having an oxygen-α, β dicarbonyl functional group structure:

[0066]

[0067] X is an alkyl or cycloalkyl group having 1 to 8 carbon atoms;

[0068] R, Y1, and Y2 are independently selected from one of H and CH3.

[0069] The structure of the light valve is shown in Figure 1 . The acrylate monomer having an oxygen-α, β-dicarbonyl functional group structure in unit (b) undergoes a heating polymerization reaction to form an acrylate copolymer, namely the suspension medium 22. Light-controlling particles 23 are distributed in the suspension medium 22 and are dispersed in the polymer matrix 21 in the form of droplets. The oxygen-α, β-dicarbonyl functional group structure in the suspension medium 22 can form a stable chelate with the metal ions in the light-controlling particles 23, thereby preventing the light-controlling particles 23 from polymerizing and decomposing due to heat, and enhancing the stability of their physical and chemical states, thereby improving the overall thermal stability of the light valve. At the same time, the oxygen-α, β-dicarbonyl functional groups also have the activity of capturing I2 molecules, and can form CI bonds, which can eliminate the purple color of trace I2 and further improve the color stability of the light valve.

[0070] In order to better illustrate the present invention, the following specific examples are provided, including various preparation examples (preparation of solid light-controlling particles, preparation of polymer matrix precursors, preparation of liquid suspension media, preparation of dimming films) and thermal stability test examples.

[0071] Example 1 Preparation of solid light-controlling particles

[0072] Add 30g of isoamyl acetate solution containing 21.2wt% nitrocellulose (model SS 1 / 4sec), 6g I2, 70g isoamyl acetate and 4g anhydrous CaI2 to a 250mL three-necked round-bottomed glass flask, and heat to 42°C. After I2 is dissolved, add 6g anhydrous methanol, 0.8g distilled water and 4g 2,5-pyrazinedicarboxylic acid dihydrate to the above three-necked round-bottomed glass flask, heat and stir at 42°C for 4 hours, and then cool naturally. The resulting reaction solution is centrifuged at 1350g for 0.5h to remove large particles of product, and then the supernatant is centrifuged at 18000g for 5h, and the supernatant is discarded to obtain solid light-controlling particles. The solid light-controlling particles are fully dispersed with 250mL of isoamyl acetate.

[0073] Example 2 Preparation of polymer matrix precursor

[0074] Add silicon-containing non-crosslinked oligomers: 54g hydroxyl-terminated dimethyldiphenylpolysiloxane and 190mL n-heptane to a 500mL three-necked round-bottomed glass flask. Connect a water separator to a condenser on one side of the three-necked round-bottomed glass flask, install a mechanical stirrer in the middle, and place a thermometer on the other side. Heat the reaction solution in the three-necked round-bottomed glass flask to reflux for 30 minutes, and add a solution of 0.13g stannous octoate dissolved in 10mL n-heptane. Then add a silicon-containing crosslinkable monomer: 3g hydrolyzed 3-acryloxypropylmethyldimethoxysilane dropwise for about 5 minutes. Then react under reflux for 2 hours, and then immediately add 30mL trimethylmethoxysilane as a terminator for the reaction; terminate the reaction for 2 hours, and then quickly cool to room temperature. Mix 50mL ethanol and the cooled reaction solution in a 1L beaker, and then wash the reaction bottle with 30mL heptane and pour it into the beaker. After mixing evenly, add 200mL methanol and stir for 15min. The resulting mixed solution was poured into a 1L separatory funnel and allowed to stand for several hours to separate into layers. The lower layer was taken out and then treated by a rotary evaporator at 70°C for 3 hours to remove low-boiling substances, and finally polysiloxane was obtained as a polymer matrix precursor.

[0075] Hydrolysis reaction: A three-necked round-bottomed glass flask is connected to a condenser on one side, a mechanical stirrer is installed in the middle, and a thermometer is placed on the other side. In a 250mL three-necked round-bottomed glass flask, 0.1g acetic acid, 5.5g water, 44.5g 3-acryloxypropylmethyldimethoxysilane, and 35mL anhydrous ethanol are added in sequence, and the hydrolysis reaction temperature is controlled to 65°C and the reaction is carried out for 5 hours. After the reaction is completed, a rotary evaporator is used to remove the solvent, the remaining water, and the acid to obtain a hydrolysis product.

[0076] Example 3 Preparation of a liquid suspension medium containing (b)

[0077] 24.4 g of dodecyl methacrylate, 2.0 g of hydroxyethyl methacrylate (a), 2.8 g of ethylene glycol methacrylate (b), 2.3 g of 1-hexanethiol, and 20 mL of toluene were added to a 250 mL three-necked round-bottomed glass flask. A mechanical stirrer is installed in the middle of the three-necked round-bottomed glass flask, one side is connected to a condenser, and the other side is placed in a thermometer and connected to argon. Before starting heating, argon is passed through the round-bottomed glass flask for about 10 minutes to completely replace the air in the round-bottomed glass flask. Then heat the flask to 60°C. At this temperature, 10 mL of toluene solution containing 0.2 g of azobisisobutyronitrile is added to the flask. The reaction temperature is maintained at 60°C for a total of 21 hours, and then the reaction temperature is increased to reflux the reaction solution for 3 hours. Stop the reaction. Then use a rotary evaporator to treat at 100°C for 3 hours to remove toluene and unreacted raw materials to obtain a liquid suspension medium 3. The suspension medium material was subjected to GPC testing, and the results are shown in Figure 2 , and its molecular weight peak is 3213.

[0078] 40 g of the obtained suspension medium was added to a 250 mL round-bottom glass flask, and the isoamyl acetate dispersion of the solid light-controlling particles prepared in Example 1 was added in batches. The isoamyl acetate was removed by a rotary evaporator. Finally, the rotary evaporator was used to continue processing at 80°C for 3 hours to obtain an example of a liquid suspension medium containing solid light-controlling particles, i.e., mixture example 3.

[0079] Example 4 Preparation of a liquid suspension medium containing (b)

[0080] 24.4g of dodecyl acrylate (a), 2.8g of ethylene glycol acetoacetate (b) shown in Table 1, 2.3g of 1-hexanethiol, and 20mL of n-heptane were added to a 250mL three-necked round-bottomed glass flask. A mechanical stirrer was installed in the middle of the three-necked round-bottomed glass flask, a condenser was connected to one side, and a thermometer was placed on the other side and connected to argon. Before starting heating, argon was passed through the round-bottomed glass flask for about 10 minutes to completely replace the air in the round-bottomed glass flask. The flask was then heated to 60°C. At this temperature, 10mL of n-heptane solution containing 0.2g of azobisisobutyronitrile was added to the flask. The reaction temperature was maintained at 60°C for a total of 21 hours, and the reaction temperature was then increased to reflux the reaction solution for 3 hours. The reaction was stopped. Then, the toluene and unreacted raw materials were removed by a rotary evaporator at 100°C for 3 hours to obtain a liquid suspension medium 4.

[0081] 40 g of the obtained suspension medium was added to a 250 mL round-bottom glass flask, and the isoamyl acetate dispersion of the solid light-controlling particles prepared in Example 1 was added in batches. The isoamyl acetate was removed by a rotary evaporator, and finally the rotary evaporator was used to continue processing at 80°C for 3 hours to obtain an example of a liquid suspension medium containing solid light-controlling particles, i.e., mixture example 4.

[0082] Example 5 Preparation of a liquid suspension medium containing (b)

[0083] The same as Example 3, except that the acrylate unit monomer (b) having an oxygen-α, β dicarbonyl functional group structure is replaced with a material having a molecular structure shown in Table 1, to obtain a liquid suspension medium 5 and an example of a liquid suspension medium containing solid light-controlling particles, i.e., mixture Example 5.

[0084] Example 6 Preparation of a liquid suspension medium containing (b)

[0085] The same as Example 3, except that the acrylate unit monomer (b) having an oxygen-α, β dicarbonyl functional group structure is replaced with a material having a molecular structure shown in Table 1, to obtain a liquid suspension medium 6 and an example of a liquid suspension medium containing solid light-controlling particles, i.e., mixture Example 6.

[0086] Example 7 Preparation of a liquid suspension medium containing (b)

[0087] The same as Example 3, except that the acrylate unit monomer (b) having an oxygen-α, β dicarbonyl functional group structure is replaced with a material having a molecular structure shown in Table 1, to obtain a liquid suspension medium 7 and an example of a liquid suspension medium containing solid light-controlling particles, i.e., mixture Example 7.

[0088] Example 8 Preparation of a liquid suspension medium containing (b)

[0089] The same as Example 3, except that the acrylate unit monomer (b) having an oxygen-α, β dicarbonyl functional group structure is replaced with a material having a molecular structure shown in Table 1, to obtain a liquid suspension medium 8 and an example of a liquid suspension medium containing solid light-controlling particles, i.e., mixture Example 8.

[0090] Example 9 Preparation of a liquid suspension medium containing (b)

[0091] The same as Example 3, except that the acrylate unit monomer (b) having an oxygen-α, β dicarbonyl functional group structure is replaced with a material having a molecular structure shown in Table 1, to obtain a liquid suspension medium 9 and an example of a liquid suspension medium containing solid light-controlling particles, i.e., mixture Example 9.

[0092] Example 10 Preparation of a liquid suspension medium containing (b)

[0093] The same as Example 4, except that the acrylate unit monomer (b) having an oxygen-α, β dicarbonyl functional group structure is replaced with a material having a molecular structure shown in Table 1, to obtain a liquid suspension medium 10 and an example of a liquid suspension medium containing solid light-controlling particles, i.e., mixture Example 10.

[0094] Example 11 Preparation of a liquid suspension medium containing (b)

[0095] The same as Example 4, except that the acrylate unit monomer (b) having an oxygen-α, β dicarbonyl functional group structure is replaced with a material having a molecular structure shown in Table 1, to obtain a liquid suspension medium 11 and an example of a liquid suspension medium containing solid light-controlling particles, i.e., mixture Example 11.

[0096] Example 12 Preparation of a liquid suspension medium containing (b)

[0097] The same as Example 4, except that the acrylate unit monomer (b) having an oxygen-α, β dicarbonyl functional group structure is replaced with a material having a molecular structure shown in Table 1, to obtain a liquid suspension medium 12 and an example of a liquid suspension medium containing solid light-controlling particles, i.e., mixture Example 12.

[0098] Table 1 Structural formula of unit (b) for preparing suspension medium in Examples 3 to 12

[0099]

[0100]

[0101] Comparative Example 1 Preparation of a liquid suspension medium without (b)

[0102] 24.4g of dodecyl methacrylate and 2.0g of hydroxyethyl methacrylate (a), 2.3g of 1-hexanethiol and 20mL of toluene were added to a 250mL three-necked round-bottomed glass flask. A mechanical stirrer was installed in the middle of the three-necked round-bottomed glass flask, a condenser was connected to one side, and a thermometer was placed on the other side and connected to argon. Before starting heating, argon was passed through the round-bottomed glass flask for about 10 minutes to completely replace the air in the round-bottomed glass flask. The flask was then heated to 60°C. At this temperature, 10mL of toluene solution containing 0.2g of azobisisobutyronitrile was added to the flask. The reaction temperature was maintained at 60°C for a total of 21 hours, and the reaction temperature was then increased to reflux the reaction solution for 3 hours. The reaction was stopped. Then the toluene and unreacted raw materials were removed by a rotary evaporator at 100°C for 3 hours to obtain a liquid suspension medium comparative example 1.

[0103] 40 g of the obtained suspension medium was added to a 250 mL round-bottom glass flask, and the isoamyl acetate dispersion of the solid light-controlling particles prepared in Example 1 was added in batches. The isoamyl acetate was removed by a rotary evaporator. Finally, the rotary evaporator was used to continue processing at 80°C for 3 hours to obtain a comparative example of a liquid suspension medium containing solid light-controlling particles, i.e., mixture comparative example 1.

[0104] Comparative Example 2 Preparation of a liquid suspension medium without (b)

[0105] 24.4g of dodecyl acrylate and 2.0g of hydroxyethyl methacrylate (a), 2.3g of 1-hexanethiol and 20mL of n-heptane were added to a 250mL three-necked round-bottomed glass flask. A mechanical stirrer was installed in the middle of the three-necked round-bottomed glass flask, a condenser was connected to one side, and a thermometer was placed on the other side and connected to argon. Before starting heating, argon was passed through the round-bottomed glass flask for about 10 minutes to completely replace the air in the round-bottomed glass flask. The flask was then heated to 60°C. At this temperature, 10mL of n-heptane solution containing 0.2g of azobisisobutyronitrile was added to the flask. The reaction temperature was maintained at 60°C for a total of 21 hours, and the reaction temperature was then increased to reflux the reaction solution for 3 hours. The reaction was stopped. Then the mixture was treated at 100°C for 3 hours by a rotary evaporator to remove toluene and unreacted raw materials to obtain a liquid suspension medium comparative example 2.

[0106] 40 g of the obtained suspension medium was added to a 250 mL round-bottom glass flask, and the isoamyl acetate dispersion of the solid light-controlling particles prepared in Example 1 was added in batches. The isoamyl acetate was removed by a rotary evaporator. Finally, the rotary evaporator was used to continue processing at 80°C for 3 hours to obtain a comparative example of a liquid suspension medium containing solid light-controlling particles, i.e., mixture comparative example 2.

[0107] Example 13 Preparation of dimming film

[0108] The initiator for initiating crosslinking and curing of the polymer matrix precursor, the mixture of the suspension medium containing solid light-controlling particles and the polymer matrix precursor are uniformly mixed, and the obtained mixture is called the light-controlling layer matrix emulsion.

[0109] 0.03 g of photoinitiator 819, 7.0 g of the polymer matrix precursor prepared in Example 2 and 3.0 g of the mixture of the liquid suspension medium containing solid light-controlling particles prepared in Examples 3 to 12 and Comparative Examples 1 to 2 were mixed evenly to obtain a light-controlling layer matrix emulsion.

[0110] The light-controlling layer matrix emulsion was coated on the ITO / PET transparent conductive film with a doctor blade type automatic coating machine (MSK-AFA-III, MTI Corporation) to a thickness of 80 μm, and another layer of ITO / PET transparent conductive film was covered on the light-controlling layer matrix emulsion wet film to obtain a light-controlling layer wet film. Then, the film was cured for 1 minute using an X200-150 UV curing machine produced by Aventk under a nitrogen atmosphere, with a UV power of 700 W / m 2 , that is, dimming films were obtained, which were respectively recorded as Examples 13 to 22 and Comparative Examples 3 to 4.

[0111] In an embodiment, a transparent conductive film (transparent electrode) is formed on a substrate of a plastic sheet.

[0112] The polymer matrix precursor is cross-linked and cured to form a polymer matrix.

[0113] Example 14: Transmittance test of dimming film

[0114] The light transmittance of the dimming film was measured using a LS116 light transmittance meter (Shenzhen Linshang Technology Co., Ltd.). When no voltage was applied (off state), the light transmittance of the dimming film was marked as Toff = %; when 60 Hz 220V AC was applied (on state), the total light transmittance of the dimming film was marked as Ton = %.

[0115] Example 15 Heat Aging Test

[0116] The test samples were thermally aged in a conventional oven at 100°C for 500 h.

[0117] The dimming films of the embodiment and the comparative example were subjected to heat aging treatment at 100°C for 500 hours in a common oven, and then the dimming performance of the dimming films after aging was tested, and the results are listed in Table 2. It can be seen that after heat aging, the performance of the dimming films of the embodiment samples 13 to 22 is more stable than that of the dimming films of the comparative examples 3 to 4. After aging treatment, the bright state transmittance of the dimming film of the comparative example 3 decreased from 60.4% before treatment to 48.4%, and the bright state transmittance of the dimming film of the comparative example 4 decreased from 60.6% before treatment to 48.9%, while the bright state transmittance of the dimming film prepared in the embodiment was basically maintained, still above 55.0%. It can be seen that the dimming film prepared by introducing the suspension medium prepared by the acrylic ester polymer containing the oxygen-α, β dicarbonyl functional group structure can achieve a more stable anti-heat aging effect compared with the product prepared by the prior art, that is, it has a longer working time, while keeping the initial performance unchanged.

[0118] Table 2 Effect of different suspension media on thermal aging performance of dimming film

[0119]

[0120] The present invention is described above by taking a light valve with a transparent plastic sheet as a substrate, namely a dimming film, as an example. Obviously, the concept of the present invention is also fully applicable to a light valve with a glass substrate, namely a dimming glass.

[0121] The description of the above embodiments is only used to help understand the method of the present invention and its core idea. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features disclosed herein.

Claims

1. A light valve, comprising: a first transparent substrate, a first transparent electrode formed on a first transparent substrate, The second transparent substrate, a second transparent electrode formed on a second transparent substrate, The first transparent electrode and the second transparent electrode are arranged opposite to each other, and A light control layer is arranged between the first transparent electrode and the second transparent electrode; the light control layer comprises a polymer matrix; suspension medium droplets are dispersed in the polymer matrix, and solid light control particles are distributed in the suspension medium droplets, characterized in that the suspension medium contains an acrylate copolymer, the acrylate copolymer has oxygen-α, β dicarbonyl functional groups, and the structure is shown in formula (A), The acrylic ester copolymer is obtained by copolymerizing the following monomers under the action of a copolymerization catalyst: (a) acrylate monomers, (b) an acrylate unsaturated monomer having oxygen-α, β dicarbonyl functional groups, the structure of which is shown in formula (B), X is an alkyl or cycloalkyl group having 1 to 8 carbon atoms; R, Y1, Y2 are independently selected from one of H or CH3; The ratio of the monomers (a) and (b) forming the acrylic ester copolymer is such that, based on 100 parts by total weight, the monomer (a) accounts for 50 to 95 parts by weight, and the monomer (b) accounts for 5 to 50 parts by weight.

2. A light valve according to claim 1, characterized in that: The (a) acrylic acid ester monomer is selected from at least one of an acrylic acid alkyl ester monomer and an acrylic acid hydroxy ester monomer.

3. A light valve according to claim 1, characterized in that: The (a) is an alkyl acrylate monomer, the general formula is CH2=CR1COO-R1' Formula (C) Wherein, R1 is CH3 or H; R1' is C n H 2n+1 , n is an integer from 1 to 18.

4. A light valve according to claim 1, characterized in that: The (a) is a hydroxy acrylate monomer, the general formula is CH2=CR2COO-R2' Formula (D) Wherein, R2 is CH3 or H; R2' is C q H 2q -OH, q is an integer of 1-8.

5. A light valve according to claim 1, characterized in that: The copolymerization catalyst is a thermally initiated free radical catalyst, which is selected from at least one of azo initiator, tributyltin hydride (n-Bu3SnH) / AIBN, ammonium persulfate, and organic peroxide.

6. A light valve according to claim 1, characterized in that: The peak molecular weight of the acrylic ester copolymer is 1,000 to 10,000.

7. A light valve according to claim 1, characterized in that: The suspension medium also includes a non-conductive liquid; the non-conductive liquid is selected from at least one of fluorocarbon organic compounds, phthalates, trimellitates, dodecylbenzene, polybutene oil, epoxidized soybean oil and epoxidized linseed oil.

8. A light valve according to claim 1, characterized in that: The solid light-controlling particles are selected from one or more of oxide nanorods, perovskite nanorods and polyiodine compound nanorods; the particle length of the solid light-controlling particles is 50 to 800 nm; and the particle aspect ratio of the solid light-controlling particles is 2 to 30.

9. A light valve according to claim 1, characterized in that: The polymer matrix is ​​a solid siloxane polymer.

10. A light valve according to claim 1, characterized in that: The first transparent substrate and the second transparent substrate are glass plates and / or transparent plastic sheets.

11. A light valve according to claim 1, characterized in that: The first transparent electrode and the second transparent electrode are each independently selected from at least one of an ITO conductive layer, a FZO conductive layer, an IZO conductive layer, a GZO conductive layer, an AZO conductive layer, a PEDOT conductive layer, a nano-Ag wire conductive layer, conductive graphene, and a nano-Cu wire conductive layer.

12. A light valve according to claim 1, characterized in that: The first transparent electrode and / or the second transparent electrode is covered with an adhesive layer, and the adhesive layer material includes at least one of epoxy resin, polyurethane resin, polyimide resin, polystyrene resin, acrylic resin, modified acrylic resin and silicone resin.

13. A thermally stable dimming glass assembly, characterized in that: Include a first glass sheet and a second glass sheet, and The light valve according to any one of claims 1 to 12 is arranged between the first glass plate and the second glass plate.

14. The thermally stable dimming glass assembly according to claim 13, characterized in that: A first interlayer is disposed between the first glass plate and the light valve, and / or a second interlayer is disposed between the second glass plate and the light valve.

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