Organosilicon binder and preparation method thereof, and foldable dimming film prepared by using organosilicon binder

Abstract

The invention belongs to the technical field of dimming films, and discloses an organic silicon binder, a preparation method thereof and a foldable dimming film prepared by using the organic silicon binder. The organic silicon binder comprises a component A and a component B, the component A comprises hydroxyl-terminated polydimethylsiloxane, vinyl-terminated polydimethylsiloxane, a modified filler and first dimethyl silicone oil; the component B comprises second dimethyl silicone oil, a silazane cross-linking agent and a catalyst; the modified filler is coupling agent modified titanium dioxide and calcium carbonate. The organic silicon adhesive provided by the invention not only has excellent adhesive property, but also can optimize the structure of a thin film layer, improve the adhesive force among the layers and provide good bonding, blocking and buffering effects; and the film also has good flexibility and transparency, can form an adhesion promoting layer, and is used for a foldable dimming film. The foldable light-adjusting film prepared by using the light-adjusting film has strong interface bonding force and bending resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of dimming films, and in particular relates to an organosilicon adhesive and a preparation method thereof, and a foldable dimming film prepared using the organosilicon adhesive. Background Art

[0002] With the widespread application of foldable displays, it is becoming more and more urgent to develop high-performance foldable dimming films that can match them. The current mass-produced dimming films mainly use ITO conductive films, which are not resistant to bending and have relatively poor flexibility, making it difficult to achieve foldability.

[0003] In order to achieve foldability, from the perspective of material structure, foldable dimming films can use flexible substrate materials such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), transparent polyimide (CPI), cellulose nanofiber (CNF), etc. These flexible substrates can withstand a certain degree of bending and folding without breaking. Therefore, the substrate problem is relatively easy to solve. However, from the manufacturing process, it is necessary to optimize the layer structure of the film and the adhesion between the layers so that the layers of material will not separate during the folding process, and the dimming function layer is firmly combined with the flexible substrate and other auxiliary layers. The current process or bonding technology cannot achieve good bonding, barrier, and buffering effects.

[0004] Therefore, it is of great significance to the development of foldable dimming films to develop bonding processes or bonding products that can optimize the film layer structure, improve the adhesion between layers, and provide good bonding, barrier, and buffering effects. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention provides an organosilicon adhesive and a preparation method thereof, and a foldable dimming film prepared using the organosilicon adhesive. The organosilicon adhesive provided by the present invention can optimize the film layer structure, improve the adhesion between the layers, and provide good bonding, barrier, and buffering effects.

[0006] The invention provides an organosilicon adhesive.

[0007] Specifically, an organosilicon adhesive includes a component A and a component B;

[0008] In parts by weight, the component A comprises 50-70 parts of hydroxyl-terminated polydimethylsiloxane, 10-25 parts of vinyl-terminated polydimethylsiloxane, 15-20 parts of modified filler and 8-15 parts of first dimethyl silicone oil;

[0009] The B component includes 50-70 parts of a second dimethyl silicone oil, 3-10 parts of a silazane crosslinking agent and 0.5-1.5 parts of a catalyst; the modified filler is coupling agent-modified titanium dioxide and calcium carbonate;

[0010] The mass ratio of the component A to the component B is (0.8-1.2):1.

[0011] It should be noted that component A and component B are sealed and stored separately before use, and the component A and the component B are mixed evenly when used.

[0012] Preferably, the preparation method of the coupling agent modified titanium dioxide and calcium carbonate is: mixing nano-sized titanium dioxide and nano-sized calcium carbonate, adding 2%-8% by mass of coupling agent solution, mixing for 30-60 minutes, and drying to obtain coupling agent modified titanium dioxide and calcium carbonate.

[0013] Preferably, the mass ratio of the nano-sized titanium dioxide to the nano-sized calcium carbonate is (2-5):1.

[0014] Preferably, the coupling agent is at least one of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane and γ-aminopropyltriethoxysilane.

[0015] Preferably, the silazane crosslinking agent is selected from hexamethyldisilazane and / or octamethylcyclotetrasilazane.

[0016] Preferably, the viscosity of the first dimethyl silicone oil at 25° C. is 200-400 mPa·s, and the viscosity of the second dimethyl silicone oil at 25° C. is 500-1200 mPa·s. Studies have shown that selecting a first dimethyl silicone oil with a viscosity of 200-400 mPa·s and a second dimethyl silicone oil with a viscosity of 500-1200 mPa·s can improve the compatibility of components A and B of the binder system, and is also beneficial to the mixing and uniform curing of components A and B.

[0017] Preferably, the catalyst is a platinum-vinyl complex or a platinum-alkyne complex.

[0018] Preferably, the component A comprises, by weight, 55-65 parts of hydroxyl-terminated polydimethylsiloxane, 10-20 parts of vinyl-terminated polydimethylsiloxane, 15-20 parts of modified filler and 8-12 parts of first dimethyl silicone oil;

[0019] The B component includes 55-65 parts of a second dimethyl silicone oil, 5-10 parts of a silazane crosslinking agent and 0.5-1.2 parts of a catalyst.

[0020] The invention also provides a method for preparing the organosilicon adhesive.

[0021] Specifically, a method for preparing an organosilicon adhesive comprises the following steps:

[0022] Prepare a modified filler by mixing hydroxyl-terminated polydimethylsiloxane, vinyl-terminated polydimethylsiloxane and a first dimethyl silicone oil, then add the modified filler under stirring, mix well, and prepare component A;

[0023] The second dimethyl silicone oil, the silazane crosslinking agent and the catalyst are mixed to prepare the B component.

[0024] The invention also provides application of the above-mentioned organosilicon adhesive.

[0025] Specifically, the application of the above-mentioned organic silicon adhesive in the preparation of a foldable dimming film. The above-mentioned organic silicon adhesive forms an adhesion promotion layer, which is arranged between the substrate layer and the conductive layer, and between the conductive layer and the PDLC layer of the foldable dimming film, and plays the role of adhesion promotion and buffering barrier, which can not only improve the adhesion between the layers, thereby improving the bending resistance; but also has buffering and barrier properties, preventing the conductive layer material from reacting with the PDLC material and the substrate.

[0026] The invention also provides a foldable dimming film.

[0027] Specifically, a foldable dimming film includes, in sequence, a first substrate layer, a first adhesion promoting layer, a first transparent conductive layer, a second adhesion promoting layer, a PDLC layer, a third adhesion promoting layer, a second transparent conductive layer, a fourth adhesion promoting layer, and a second substrate layer;

[0028] The first adhesion promoting layer, the second adhesion promoting layer, the third adhesion promoting layer, and the fourth adhesion promoting layer are respectively prepared by coating and curing the above-mentioned organic silicon adhesive.

[0029] Preferably, the first substrate layer and the second substrate layer are independently selected from one of PET, PEN, CPI and CNF.

[0030] Preferably, the thickness of the first substrate layer and the second substrate layer is less than or equal to 50 μm, and the haze is ≤1%; further preferably, the thickness of the first substrate layer and the second substrate layer is 10-30 μm, and the haze is ≤0.5%.

[0031] Preferably, the first transparent conductive layer and the second transparent conductive layer are independently made of a conductive polymer, and the conductive polymer is selected from one of polypyrrole (PPy), polyaniline (PANI) and poly (3,4-ethylenedioxythiophene) (PEDOT:PSS). The square resistance of the first transparent conductive layer and the second transparent conductive layer is 40-100Ω.

[0032] The organosilicon adhesive provided by the present invention is composed of two components A and B, wherein a certain proportion of end-vinyl polydimethylsiloxane in component A is used to replace the hydroxyl-terminated polydimethylsiloxane of the silicone rubber-based glue, which can not only dilute the system before the A and B components are mixed, but also increase the degree of crosslinking of the system after mixing, which is beneficial to improving the bonding performance and flexibility of the adhesive. At the same time, in the organosilicon adhesive system of the present invention, silazanes are used as crosslinking agents, and the crosslinking between silazanes and organosilicon polymer molecular chains containing hydroxyl groups can improve the bonding performance of the adhesive and improve the adhesion of the adhesive to each layer. In addition, the present invention uses a coupling agent to simultaneously modify a certain proportion of titanium dioxide and calcium carbonate to obtain a modified filler, which can not only fully mix the two in advance during the modification; but also enable the two to interact during the modification process, which promotes the bonding effect and flexibility of the organosilicon adhesive.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) The organosilicon adhesive provided by the present invention not only has excellent bonding properties, can optimize the film layer structure, improve the adhesion between the layers, and provide good bonding, barrier, and buffering effects; but also has good flexibility and transparency, and can form an adhesion-promoting layer for use in foldable dimming films.

[0035] (2) The foldable dimming film provided by the present invention has strong interface bonding strength and is resistant to bending. The layers will not separate or be damaged during the bending process. It can be widely used in foldable display screens and skylight glass with a large curvature. DETAILED DESCRIPTION

[0036] In order to make the technical scheme of the present invention more clearly understood by those skilled in the art, the following embodiments are listed for illustration. It should be pointed out that the following embodiments do not limit the protection scope of the present invention.

[0037] Unless otherwise specified, the raw materials, reagents or devices used in the following examples and comparative examples can be obtained from conventional commercial sources or by existing known methods.

[0038] Example 1

[0039] A silicone adhesive comprises a component A and a component B, wherein the mass ratio of the component A to the component B is 1:1; in parts by weight, the component A comprises 60 parts of hydroxyl-terminated polydimethylsiloxane, 15 parts of vinyl-terminated polydimethylsiloxane, 16 parts of modified fillers and 10 parts of a first dimethyl silicone oil; the component B comprises 60 parts of a second dimethyl silicone oil, 6 parts of hexamethyldisilazane and 1 part of a platinum-vinyl complex;

[0040] Among them, the modified filler is coupling agent modified titanium dioxide and calcium carbonate;

[0041] The viscosity of the first dimethyl silicone oil at 25° C. is about 300 mPa·s, and the viscosity of the second dimethyl silicone oil at 25° C. is about 1000 mPa·s.

[0042] A method for preparing an organosilicon adhesive comprises the following steps:

[0043] (1) mixing nano-sized titanium dioxide and nano-sized calcium carbonate in a mass ratio of 3:1, then adding 3 times the mass of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane solution (mass percentage 6%), mixing for 40 minutes, and performing solid-liquid separation and drying to obtain a modified filler;

[0044] (2) mixing hydroxyl-terminated polydimethylsiloxane, vinyl-terminated polydimethylsiloxane and the first dimethyl silicone oil, and then adding the modified filler under stirring, mixing evenly, to obtain component A;

[0045] (3) Mix the second dimethyl silicone oil, the silazane crosslinking agent and the catalyst to prepare component B.

[0046] Example 2

[0047] A silicone adhesive comprises a component A and a component B, wherein the mass ratio of the component A to the component B is 1:1; in parts by weight, the component A comprises 62 parts of hydroxyl-terminated polydimethylsiloxane, 13 parts of vinyl-terminated polydimethylsiloxane, 15 parts of modified fillers and 8 parts of a first dimethyl silicone oil; the component B comprises 58 parts of a second dimethyl silicone oil, 8 parts of hexamethyldisilazane and 1 part of a platinum-vinyl complex;

[0048] Among them, the modified filler is coupling agent modified titanium dioxide and calcium carbonate;

[0049] The viscosity of the first dimethyl silicone oil at 25° C. is about 250 mPa·s, and the viscosity of the second dimethyl silicone oil at 25° C. is about 900 mPa·s.

[0050] A method for preparing an organosilicon adhesive comprises the following steps:

[0051] (1) nano-sized titanium dioxide and nano-sized calcium carbonate were mixed in a mass ratio of 4:1, and then 3 times the mass of γ-aminopropyltrimethoxysilane solution (mass percentage 6%) was added, and the mixture was mixed for 40 minutes, and solid-liquid separation and drying were performed to obtain a modified filler;

[0052] (2) mixing hydroxyl-terminated polydimethylsiloxane, vinyl-terminated polydimethylsiloxane and the first dimethyl silicone oil, and then adding the modified filler under stirring, mixing evenly, to obtain component A;

[0053] (3) Mix the second dimethyl silicone oil, the silazane crosslinking agent and the catalyst to prepare component B.

[0054] Example 3

[0055] A silicone adhesive comprises a component A and a component B, wherein the mass ratio of the component A to the component B is 1:1; in parts by weight, the component A comprises 67 parts of hydroxyl-terminated polydimethylsiloxane, 23 parts of vinyl-terminated polydimethylsiloxane, 18 parts of modified fillers and 12 parts of a first dimethyl silicone oil; the component B comprises 68 parts of a second dimethyl silicone oil, 5 parts of hexamethyldisilazane and 1 part of a platinum-vinyl complex;

[0056] Among them, the modified filler is coupling agent modified titanium dioxide and calcium carbonate;

[0057] The viscosity of the first dimethyl silicone oil at 25° C. is about 250 mPa·s, and the viscosity of the second dimethyl silicone oil at 25° C. is about 900 mPa·s.

[0058] A method for preparing an organosilicon adhesive comprises the following steps:

[0059] (1) nano-sized titanium dioxide and nano-sized calcium carbonate were mixed in a mass ratio of 4:1, and then 3 times the mass of γ-aminopropyltrimethoxysilane solution (mass percentage 6%) was added, and the mixture was mixed for 40 minutes, and solid-liquid separation and drying were performed to obtain a modified filler;

[0060] (2) mixing hydroxyl-terminated polydimethylsiloxane, vinyl-terminated polydimethylsiloxane and the first dimethyl silicone oil, and then adding the modified filler under stirring, mixing evenly, to obtain component A;

[0061] (3) Mix the second dimethyl silicone oil, the silazane crosslinking agent and the catalyst to prepare component B.

[0062] Example 4

[0063] A silicone adhesive comprises a component A and a component B, wherein the mass ratio of the component A to the component B is 1:1; in parts by weight, the component A comprises 60 parts of hydroxyl-terminated polydimethylsiloxane, 15 parts of vinyl-terminated polydimethylsiloxane, 16 parts of modified fillers and 10 parts of a first dimethyl silicone oil; the component B comprises 60 parts of a second dimethyl silicone oil, 6 parts of hexamethyldisilazane and 1 part of a platinum-vinyl complex;

[0064] Among them, the modified filler is coupling agent modified titanium dioxide and calcium carbonate;

[0065] The viscosity of the first dimethyl silicone oil at 25° C. is about 300 mPa·s, and the viscosity of the second dimethyl silicone oil at 25° C. is about 1000 mPa·s.

[0066] A method for preparing an organosilicon adhesive comprises the following steps:

[0067] (1) adding nano-sized titanium dioxide to 3 times the mass of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane solution (6% by mass), mixing for 40 minutes, solid-liquid separation, and drying to obtain modified titanium dioxide; adding nano-sized calcium carbonate to 3 times the mass of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane solution (6% by mass), mixing for 40 minutes, solid-liquid separation, and drying to obtain modified calcium carbonate; and mixing the modified titanium dioxide and the modified calcium carbonate in a mass ratio of 3:1 to obtain a modified filler;

[0068] (2) mixing hydroxyl-terminated polydimethylsiloxane, vinyl-terminated polydimethylsiloxane and the first dimethyl silicone oil, and then adding the modified filler under stirring, mixing evenly, to obtain component A;

[0069] (3) Mix the second dimethyl silicone oil, the silazane crosslinking agent and the catalyst to prepare component B.

[0070] Example 5

[0071] The difference between this embodiment and embodiment 1 is that the viscosity of the first dimethyl silicone oil used at 25° C. is about 500 mPa·s, and the viscosity of the second dimethyl silicone oil used at 25° C. is about 1500 mPa·s. The remaining components and preparation method are the same as those in embodiment 1.

[0072] Comparative Example 1

[0073] The difference between this comparative example and Example 1 is that 15 parts of vinyl-terminated polydimethylsiloxane are replaced by an equal amount of hydroxy-terminated polydimethylsiloxane, and the remaining components and preparation method are the same as those in Example 1.

[0074] Comparative Example 2

[0075] The difference between this comparative example and Example 1 is that the filler in component A is not modified, that is, 12 parts of nano-sized titanium dioxide and 4 parts of nano-sized calcium carbonate are directly used, and the remaining components and preparation method are the same as those in Example 1.

[0076] Comparative Example 3

[0077] The difference between this comparative example and Example 1 is that the modified filler in component A is equal amounts of coupling agent-modified silica and calcium carbonate, and the preparation method of the coupling agent-modified silica and calcium carbonate is: nano-scale silica and nano-scale calcium carbonate are mixed in a mass ratio of 3:1, and then 3 times the mass of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane solution (mass percentage 6%) is added, mixed for 40 minutes, and dried to obtain the modified filler. The remaining components and preparation methods are the same as in Example 1.

[0078] Comparative Example 4

[0079] The difference between this comparative example and Example 1 is that the crosslinking agent hexamethyldisilazane in component B is replaced by an equal amount of hydrogen-containing silicone oil. The remaining components and preparation method are the same as those in Example 1.

[0080] Application Examples

[0081] A foldable dimming film comprises, in sequence, a first substrate layer (CPI, 20 μm, haze ≤ 0.5%), a first adhesion promoting layer (5 μm), a first transparent conductive layer (poly (3,4-ethylenedioxythiophene), 0.78 μm, resistance 100Ω), a second adhesion promoting layer (0.5 μm), a PDLC layer (15 μmμm), a third adhesion promoting layer (0.5 μm), a second transparent conductive layer (poly (3,4-ethylenedioxythiophene), 0.78 μm), a fourth adhesion promoting layer (5 μm), and a second substrate layer (CPI, 20 μm, haze ≤ 0.5%).

[0082] The preparation method is as follows:

[0083] (1) A transparent rolled CPI base film with a center thickness of 20 μm is selected as the first substrate layer, and a layer of the organic silicone adhesive provided in the above embodiment or comparative example is first coated on the CPI base film (each adhesion-promoting layer in the same foldable dimming film uses the same organic silicone adhesive provided in the embodiment or comparative example), and then thermally cured to form a first adhesion-promoting layer.

[0084] (2) Poly(3,4-ethylenedioxythiophene) (PEDOT:PSS) is coated on the first adhesion promoting layer, and after coating, thermal curing is performed at 130° C. for 5 minutes to obtain a first transparent conductive layer with a sheet resistance of 100Ω.

[0085] (3) A layer of the organic silicon adhesive provided in the above embodiment or comparative example is coated on the first transparent conductive layer, and then heat cured to form a second adhesion promoting layer. After coating, the film is divided into two rolls for standby use. That is, a roll of film containing the first substrate layer, the first adhesion promoting layer, the first transparent conductive layer, and the second adhesion promoting layer, and a roll of film containing the second substrate layer, the fourth adhesion promoting layer, the second transparent conductive layer, and the third adhesion promoting layer are prepared at the same time.

[0086] (4) Prepare a PDLC material, which is a Xingye low-voltage PDLC material (specifically refer to the preparation method of PDLC in the specific embodiment 1 of patent CN201610958214.9). The PDLC material is coated between the second adhesion promoting layer and the third adhesion promoting layer by roller coating, and compounded and cured to form a PDLC layer to obtain a foldable dimming film.

[0087] Product effect testing

[0088] Performance tests were performed on the organosilicon adhesives provided in the embodiments and comparative examples, and the foldable dimming films provided in the application examples.

[0089] 1. Test the light transmittance of the organosilicon adhesive provided in the examples and comparative examples. The specific method is: mix the A and B components of the organosilicon adhesive provided in each example and comparative example, weigh a small amount into a quartz dish, and then test the light transmittance in the range of 400-800nm ​​after fully curing. The test results are shown in Table 1.

[0090] 2. The adhesion of the organic silicon adhesive provided in the examples and comparative examples on the CPI base film and the poly(3,4-ethylenedioxythiophene) transparent conductive layer was tested according to standard ASTM D3359-2022. The test results are shown in Table 1.

[0091] 3. Test the bending resistance of the foldable dimming film prepared by using the organic silicon adhesive in each embodiment and comparative example. The specific method is: use a bending machine to test whether the sample has peeling, breaking, whitening, etc. after being bent 2000 times at 90 degrees. The test results are shown in Table 2.

[0092] Table 1

[0093]

[0094] It can be seen from Table 1 that the organosilicon adhesive provided by the embodiment of the present invention has high light transmittance, excellent bonding performance, good adhesion to the substrate and the conductive layer, and its effect is significantly better than that of the comparative example.

[0095] Table 2

[0096]

[0097] It can be seen from Table 2 that the foldable dimming film prepared using the silicone adhesive provided in the embodiment of the present invention has good bending resistance. After being bent 90 degrees for 2000 times, the sample basically does not peel off or break. It can be widely used in foldable display screens and skylight glass with a large curvature.

[0098] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A silicone adhesive, characterized in that: It includes component A and component B; In parts by weight, the component A comprises 50-70 parts of hydroxyl-terminated polydimethylsiloxane, 10-25 parts of vinyl-terminated polydimethylsiloxane, 15-20 parts of modified filler and 8-15 parts of first dimethyl silicone oil; The B component includes 50-70 parts of a second dimethyl silicone oil, 3-10 parts of a silazane crosslinking agent and 0.5-1.5 parts of a catalyst; the modified filler is coupling agent-modified titanium dioxide and calcium carbonate; The mass ratio of the component A to the component B is (0.8-1.2):

1.

2. The organosilicon adhesive according to claim 1, characterized in that: The preparation method of the coupling agent modified titanium dioxide and calcium carbonate is as follows: nano-sized titanium dioxide and nano-sized calcium carbonate are mixed, a coupling agent solution with a mass percentage of 2%-8% is added, the mixture is mixed for 30-60 minutes, and the coupling agent modified titanium dioxide and calcium carbonate are obtained after drying.

3. The organosilicon adhesive according to claim 2, characterized in that: The mass ratio of the nano-sized titanium dioxide to the nano-sized calcium carbonate is (2-5):

1.

4. The organosilicon adhesive according to claim 1 or 2, characterized in that: The silazane crosslinking agent is selected from hexamethyldisilazane and / or octamethylcyclotetrasilazane.

5. The organosilicon adhesive according to claim 1 or 2, characterized in that: The viscosity of the first dimethyl silicone oil at 25° C. is 200-400 mPa·s, and the viscosity of the second dimethyl silicone oil at 25° C. is 500-1200 mPa·s.

6. The method for preparing the organosilicon adhesive according to any one of claims 1 to 5, characterized in that: The following steps are involved: Prepare a modified filler by mixing hydroxyl-terminated polydimethylsiloxane, vinyl-terminated polydimethylsiloxane and a first dimethyl silicone oil, then add the modified filler under stirring, mix well, and prepare component A; The second dimethyl silicone oil, the silazane crosslinking agent and the catalyst are mixed to prepare the B component.

7. Use of the organosilicon adhesive according to any one of claims 1 to 5 in preparing a foldable dimming film.

8. A foldable dimming film, characterized in that: The method comprises, in sequence, a first substrate layer, a first adhesion promoting layer, a first transparent conductive layer, a second adhesion promoting layer, a PDLC layer, a third adhesion promoting layer, a second transparent conductive layer, a fourth adhesion promoting layer, and a second substrate layer; The first adhesion promoting layer, the second adhesion promoting layer, the third adhesion promoting layer, and the fourth adhesion promoting layer are respectively prepared by coating and curing the organic silicon adhesive according to any one of claims 1 to 5.

9. The foldable dimming film according to claim 8, characterized in that: The first substrate layer and the second substrate layer are independently selected from one of PET, PEN, CPI, and CNF; the thickness of the first substrate layer and the second substrate layer is less than or equal to 50 μm, and the haze is ≤1%.

10. The foldable dimming film according to claim 8, characterized in that: The first transparent conductive layer and the second transparent conductive layer are independently made of conductive polymers, and the conductive polymer is selected from one of polypyrrole, polyaniline and poly(3,4-ethylenedioxythiophene).

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