Highly flexible transparent conductive shielding film and preparation method thereof

Abstract

The present invention discloses a highly flexible transparent conductive shielding film and a method for preparing the same. The highly flexible transparent conductive shielding film comprises the following components in parts by weight: 24-36 parts of a modified epoxy resin, 1-3 parts of a composite polythiophene copolymer, 8-13 parts of an ethylene-vinyl acetate copolymer, 2-3 parts of benzophenone, 1-3 parts of triallyl isocyanurate, 0.5-1.1 parts of toluene, 1-3 parts of N,N-dimethylformamide, 2-5 parts of dopamine hydrochloride, and 2-5 parts of tris(hydroxymethyl)aminomethane. The modified epoxy resin and the composite polythiophene copolymer are added to the ethylene-vinyl acetate copolymer to form the main material of the conductive shielding film. The modified epoxy resin has excellent flexibility and high-temperature resistance, and the composite polythiophene copolymer has excellent shielding properties, resulting in a conductive shielding film having excellent flexibility, shielding properties, and high-temperature resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of transparent conductive shielding films, and in particular relates to a highly flexible transparent conductive shielding film and a preparation method thereof. Background Art

[0002] Highly flexible, transparent conductive shielding films have broad application prospects across multiple fields. In electronic displays, they can be used to create high-performance touchscreens and displays, enhancing the user experience. In solar cells, they can serve as transparent electrodes, increasing the photoelectric conversion efficiency of solar cells. In the military industry, they can be used to create stealth materials and electromagnetic shielding materials, improving the performance of weaponry. With the continuous advancement of science and technology, the technology for highly flexible, transparent conductive shielding films is also advancing. We will continue to explore new material systems and preparation processes to further improve the material's performance and expand its application areas.

[0003] Patent CN 110708945 B discloses an opaque film for electromagnetic shielding. The film comprises a polymer film substrate filled with conductive and magnetic particles, a silicon oxide film coated on at least a portion of the polymer film substrate, and the magnetic particles are concentrated on the outer surface of the polymer film substrate. The resulting opaque film for electromagnetic shielding combines good flexibility with electromagnetic shielding performance and exhibits excellent environmental stability, effectively isolating the film material from the effects of water and oxygen. However, the flexibility, conductivity, electromagnetic shielding efficiency, and high-temperature resistance of the film produced using this method still require improvement. Summary of the Invention

[0004] The purpose of the present invention is to provide a highly flexible transparent conductive shielding film and a preparation method thereof, so as to solve the technical problems of poor flexibility, conductivity, electromagnetic shielding rate and high temperature resistance of the conductive shielding film in the prior art.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a highly flexible transparent conductive shielding film, which is composed of the following components in parts by weight: 24-36 parts of a modified epoxy resin, 1-3 parts of a composite polythiophene copolymer, 8-13 parts of an ethylene-vinyl acetate copolymer, 2-3 parts of benzophenone, 1-3 parts of triallyl isocyanurate, 0.5-1.1 parts of toluene, 1-3 parts of N,N-dimethylformamide, 2-5 parts of dopamine hydrochloride, and 2-5 parts of tris(hydroxymethyl)aminomethane; wherein the modified epoxy resin is obtained by reacting a polyether diol, 2,4-diisocyanatotoluene and bisphenol A diglycidyl ether, and the composite polythiophene copolymer is obtained by compounding tetrahydrofuran, thiophene-3-acetic acid, triethylamine, pentafluorophenyl trifluoroacetate, isopropyl magnesium chloride and Ni(dppp)Cl2.

[0007] Preferably, the preparation method of the modified epoxy resin comprises the following steps:

[0008] Q1: The polyether diol is placed in a vacuum drying oven for vacuum dehydration and then mixed evenly with 2,4-diisocyanate toluene, followed by heating for reaction. After the reaction is completed, a polyurethane prepolymer is obtained;

[0009] Q2: Mix and stir the polyurethane prepolymer and bisphenol A diglycidyl ether, increase the temperature, add 2-methyl-4-ethylimidazole to obtain a mixture, add 2,4-diisocyanate to the mixture dropwise using a constant pressure dropping funnel, increase the temperature after the addition is complete, and react to obtain a modified epoxy resin.

[0010] In the above process, the hydroxyl groups in the polyether diol react with the isocyanate groups in 2,4-diisocyanatotoluene to form carbamate bonds to obtain a polyurethane prepolymer; the polyurethane prepolymer is then mixed with bisphenol A diglycidyl ether in the presence of 2-methyl-4-ethylimidazole as a catalyst to obtain a polyurethane-epoxy resin hybrid material. The addition of 2,4-diisocyanatotoluene can react with the remaining hydroxyl groups or amino groups in the mixed system to enhance the crosslinking density, toughness and high-temperature resistance of the modified epoxy resin.

[0011] Preferably, in Q1, the relative molecular mass of the polyether diol is 600, the temperature of the vacuum drying oven is 100-130°C, the time is 2-3h, the molar ratio of the polyether diol and 2,4-diisocyanate toluene is 1:(1.7-2.3), the heating reaction is carried out in a nitrogen-filled atmosphere, the heating temperature is 60-80°C, and the reaction time is 7-10h; in Q2, the heating temperature is 90-110°C, and the heating temperature is 140-160°C.

[0012] Preferably, the preparation method of the composite polythiophene copolymer comprises the following steps:

[0013] S1: Tetrahydrofuran and thiophene-3-acetic acid were added to a flask, and triethylamine and pentafluorophenyl trifluoroacetate were added dropwise under ice-water bath. After the addition was completed, the mixture was stirred, rotary evaporated, and ethyl acetate was added to dissolve the mixture. The mixture was washed, extracted, dried, filtered, and purified to obtain product 1.

[0014] S2: Anhydrous ferric chloride and chloroform are stirred under argon protection to obtain a suspension, product 1 is dissolved in chloroform and quickly added to the suspension, stirred, and then methanol is added. The mixture is filtered, extracted, and dried in vacuo to obtain product 2;

[0015] S3: Add product 2 and N,N-dimethylformamide to a round-bottom flask, stir in a water bath, add triethylamine and N,N-dimethyl-1,3-propylenediamine, continue stirring, cool, dialyze, filter, and lyophilize to obtain product 3;

[0016] S4: Add product 3 and N,N-dimethylformamide to a round-bottom flask, stir in an oil bath, add 1-n-bromobutane, and continue the reaction. After the reaction is completed, cool, dialyze, rotary evaporate, filter, and freeze-dry to obtain product 4;

[0017] S5: The product 4 was vacuumed under an oil pump to replace nitrogen, tetrahydrofuran and isopropylmagnesium chloride were added, and stirred, and then Ni(dppp)Cl2 was added, and the reaction was continued. The mixture was centrifuged and dried to obtain a composite polythiophene copolymer.

[0018] In the above process, a composite polythiophene copolymer is obtained through esterification reaction, Lewis acid-catalyzed polymerization reaction, amination reaction, alkylation reaction and metal organic reaction.

[0019] Preferably, in S1, the amount ratio of tetrahydrofuran, thiophene-3-acetic acid, triethylamine and pentafluorophenyl trifluoroacetate is (140-160) mL: (4-6) g: (19-20) mL: (11.8-12.4) mL, the stirring time is 1-2 h, and the drying time is 20-24 h; in S2, the amount ratio of anhydrous ferric chloride and chloroform is (1.8-2.1) g: (28-32) mL, the stirring time is 30-45 min, the amount ratio of product 1 and chloroform is (0.8-1.1) g: (8-12) mL, the extraction time is 3-4 days, and the vacuum drying time is 20-24 h.

[0020] Preferably, in S3, the amount ratio of product 2, N,N-dimethylformamide, triethylamine and N,N-dimethyl-1,3-propylenediamine is (0.1-0.2) g: (20-40) mL: (0.045-0.091) mL: (0.065-0.131) g, the water bath temperature is 50-60°C, the stirring time is 30-40 min, the continued stirring time is 40-50 h, the dialysis molecular weight cutoff is 3500 Da, and the dialysis time is 3-5 days.

[0021] Preferably, in S4, the amount ratio of product 3, N,N-dimethylformamide and 1-bromobutane is (0.1-0.3) g: (10-30) mL: (3-9) mL, the oil bath temperature is 50-60°C, the reaction time is continued for 6-8 hours, and the dialysis time is 2-4 days; in S5, the amount ratio of product 4, tetrahydrofuran, isopropylmagnesium chloride and Ni(dppp)Cl2 is (0.1-0.2) g: (2-4) mL: (0.2-0.4) mL: (0.011-0.022) g, and the reaction time is continued for 1-3 hours.

[0022] Preferably, the method for preparing the highly flexible transparent conductive shielding film comprises the following steps:

[0023] Step (1): Ethylene-vinyl acetate copolymer, benzophenone and triallyl isocyanurate are mixed and dissolved in a mixed solution of toluene and N,N-dimethylformamide, and modified epoxy resin and composite polythiophene copolymer are added to obtain a fiber membrane precursor solution, and a composite fiber membrane is obtained by electrospinning technology;

[0024] Step (2): dopamine hydrochloride and tris(hydroxymethyl)aminomethane) are mixed and added to deionized water, and stirred to obtain a dopamine solution. The composite fiber membrane is immersed in the dopamine solution and continuously stirred. After the stirring is completed, the composite fiber membrane is placed in deionized water for ultrasonic treatment. After drying, a highly flexible transparent conductive shielding film is obtained.

[0025] In the above process, dopamine hydrochloride and tris(hydroxymethylaminomethane) are mixed and stirred in ionized water to obtain a dopamine solution. Under alkaline conditions, the composite fiber membrane is placed in the dopamine solution, and the dopamine molecules undergo self-polymerization reaction on the fiber surface to form a polydopamine layer.

[0026] Preferably, in step (1), the mixing time is 5-7 hours, and the parameters of the electrospinning technology are: ambient temperature is 28-32° C., relative humidity is 40-50%, and the rotation speed of the collecting drum is 100-120 rpm.

[0027] Preferably, in step (2), the stirring time is 20-24 hours, and the ultrasonic treatment time is 5-10 minutes.

[0028] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0029] 1. The present invention first uses polyether diol, 2,4-diisocyanatotoluene and bisphenol A diglycidyl ether as raw materials to synthesize a modified epoxy resin, and then uses tetrahydrofuran, thiophene-3-acetic acid, triethylamine, pentafluorophenyl trifluoroacetate, isopropyl magnesium chloride and Ni(dppp)Cl2 as main raw materials to synthesize a composite polythiophene copolymer, and the modified epoxy resin, the composite polythiophene copolymer and ethylene-vinyl acetate copolymer are mixed, and a composite fiber membrane is obtained by electrospinning technology. Subsequently, the composite fiber membrane is placed in a dopamine solution for immersion to obtain a highly flexible transparent conductive shielding film with excellent shielding performance, flexibility and high temperature resistance.

[0030] 2. The present invention utilizes polyether diol, 2,4-toluene diisocyanate and bisphenol A diglycidyl ether as raw materials to synthesize modified epoxy resin; by introducing the flexible chain segment of the polyether diol, the modified epoxy resin has excellent flexibility and can be deformed more easily when subjected to external force. The generated urethane bonds can enhance the connection between molecules and improve the mechanical properties and stability of the material. Bisphenol A diglycidyl ether, as a precursor of the epoxy resin, forms a three-dimensional network structure through a cross-linking reaction, giving the modified epoxy resin excellent thermal stability and mechanical strength; and the polar groups and conductive network in the modified epoxy resin reflect and absorb electromagnetic waves, reducing the transmission of electromagnetic waves and improving shielding performance.

[0031] 3. The present invention utilizes tetrahydrofuran, thiophene-3-acetic acid, triethylamine, pentafluorophenyl trifluoroacetate, isopropyl magnesium chloride and Ni(dppp)Cl2 as main raw materials to synthesize a composite polythiophene copolymer. The thiophene group in the substance has a conjugated structure, which can provide a channel for electron transmission, so that the copolymer has good electrical conductivity. The intermolecular arrangement and interaction of the composite polythiophene copolymer can make the copolymer maintain high transparency and improve the optical properties of the shielding film. The interaction and compatibility between the composite polythiophene copolymer and the modified epoxy resin can jointly bear the external force and improve the flexibility of the overall conductive shielding film.

[0032] 4. The present invention places the composite fiber membrane in a dopamine solution for immersion, and finally obtains a conductive shielding membrane. Under alkaline conditions, the phenolic hydroxyl and amino groups in the dopamine molecules undergo oxidation-reduction reaction to form polydopamine. The π electron conjugated system in polydopamine gives it good conductive properties. When the polydopamine layer is attached to the surface of the fiber membrane, a continuous conductive network can be formed to improve the conductive properties of the conductive shielding membrane; and the functional groups such as catechol and amino groups in the polydopamine molecules can form strong chemical bonds and hydrogen bonds with other materials, showing excellent adhesion, so that the polydopamine layer can be firmly attached to the surface of the fiber membrane and is not easy to fall off. DETAILED DESCRIPTION

[0033] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0034] Example 1

[0035] This embodiment discloses a method for preparing a modified epoxy resin, comprising the following steps:

[0036] Q1: 2.028 g of polyether diol with a relative molecular mass of 600 was placed in a vacuum drying oven at 100°C for 3 h and then mixed evenly with 1.175 g of 2,4-toluene diisocyanate. The mixture was then heated in a nitrogen atmosphere at 70°C for 8 h to obtain a polyurethane prepolymer.

[0037] Q2: Mix and stir the polyurethane prepolymer and bisphenol A diglycidyl ether, raise the temperature to 110°C, add 2-methyl-4-ethylimidazole to obtain a mixture, add 2,4-diisocyanate to the mixture dropwise using a constant pressure dropping funnel, and after the addition is complete, raise the temperature to 150°C for reaction to obtain a modified epoxy resin.

[0038] This embodiment discloses a method for preparing a composite polythiophene copolymer, comprising the following steps:

[0039] S1: Add 150 mL of tetrahydrofuran and 5 g of thiophene-3-acetic acid to a flask, then add 19.5 mL of triethylamine and 12.1 mL of pentafluorophenyl trifluoroacetate dropwise in an ice-water bath. After the addition is complete, stir for 2 h, rotary evaporation, add ethyl acetate to dissolve, wash, extract, dry for 24 h, filter, and purify to obtain product 1;

[0040] S2: 1.9 g of anhydrous ferric chloride and 30 mL of chloroform were stirred under argon for 30 min to obtain a suspension. 0.9 g of product 1 was dissolved in 10 mL of chloroform and quickly added to the suspension, stirred, and then methanol was added. The mixture was filtered, extracted for 3 days, and vacuum dried for 24 h to obtain product 2.

[0041] S3: 0.15 g of product 2 and 30 mL of N,N-dimethylformamide were added to a round-bottom flask, stirred in a water bath at 60°C for 30 min, 0.075 mL of triethylamine and 0.103 g of N,N-dimethyl-1,3-propylenediamine were added, and stirring was continued for 48 h. After cooling, the product was dialyzed for 3 days with a molecular weight cutoff of 3500 Da. The product was filtered and lyophilized to obtain product 3.

[0042] S4: 0.2 g of product 3 and 20 mL of N,N-dimethylformamide were added to a round-bottom flask, stirred in an oil bath at 60°C, and then 5.5 mL of 1-n-bromobutane was added. The reaction was continued for 8 h. After the reaction was completed, the mixture was cooled, dialyzed for 3 days, rotary evaporated, filtered, and freeze-dried to obtain product 4.

[0043] S5: 0.15 g of product 4 was evacuated under an oil pump to replace nitrogen, 3 mL of tetrahydrofuran and 0.3 mL of isopropylmagnesium chloride were added, and the mixture was stirred. Subsequently, 0.018 g of Ni(dppp)Cl2 was added, and the reaction was continued for 2 h. The mixture was centrifuged and dried to obtain a composite polythiophene copolymer.

[0044] This embodiment discloses a highly flexible transparent conductive shielding film, composed of the following components in parts by weight: 30 parts of modified epoxy resin, 2 parts of composite polythiophene copolymer, 10.5 parts of ethylene-vinyl acetate copolymer, 2.5 parts of benzophenone, 2 parts of triallyl isocyanurate, 0.8 part of toluene, 1 part of N,N-dimethylformamide, 3.5 parts of dopamine hydrochloride, and 3.5 parts of tris(hydroxymethyl)aminomethane.

[0045] This embodiment discloses a method for preparing a highly flexible transparent conductive shielding film, comprising the following steps:

[0046] Step (1): Ethylene-vinyl acetate copolymer, benzophenone and triallyl isocyanurate are mixed for 7 hours and then dissolved in a mixed solution of toluene and N,N-dimethylformamide, and a modified epoxy resin and a composite polythiophene copolymer are added to obtain a fiber membrane precursor solution, and a composite fiber membrane is obtained by electrospinning technology, wherein the parameters of the electrospinning technology are: ambient temperature of 30° C., relative humidity of 45%, and a collection drum rotation speed of 120 rpm;

[0047] Step (2): dopamine hydrochloride and tris(hydroxymethyl)aminomethane) are mixed and added to deionized water, and stirred for 24 hours to obtain a dopamine solution. The composite fiber membrane is immersed in the dopamine solution and continuously stirred. After stirring, it is placed in deionized water for ultrasonic treatment for 10 minutes. After drying, a highly flexible transparent conductive shielding film is obtained.

[0048] Example 2

[0049] This embodiment discloses a method for preparing a modified epoxy resin, comprising the following steps:

[0050] Q1: 2.028 g of polyether diol with a relative molecular mass of 600 was placed in a vacuum drying oven at 100°C for 3 h and then mixed evenly with 1.004 g of 2,4-toluene diisocyanate. The mixture was then heated in a nitrogen atmosphere at 70°C for 8 h to obtain a polyurethane prepolymer.

[0051] Q2: Mix and stir the polyurethane prepolymer and bisphenol A diglycidyl ether, raise the temperature to 110°C, add 2-methyl-4-ethylimidazole to obtain a mixture, add 2,4-diisocyanate to the mixture dropwise using a constant pressure dropping funnel, and after the addition is complete, raise the temperature to 150°C for reaction to obtain a modified epoxy resin.

[0052] This embodiment discloses a method for preparing a composite polythiophene copolymer, comprising the following steps:

[0053] S1: 145 mL of tetrahydrofuran and 4 g of thiophene-3-acetic acid were added to a flask. 19 mL of triethylamine and 11.8 mL of pentafluorophenyl trifluoroacetate were added dropwise under ice-water bath conditions. After the addition was complete, the mixture was stirred for 2 h, rotary evaporated, and ethyl acetate was added for dissolution. The mixture was washed, extracted, dried for 24 h, filtered, and purified to obtain product 1.

[0054] S2: 1.8 g of anhydrous ferric chloride and 28 mL of chloroform were stirred under argon for 30 min to obtain a suspension. 0.8 g of product 1 was dissolved in 8 mL of chloroform and quickly added to the suspension, stirred, and then methanol was added. The mixture was filtered, extracted for 3 days, and vacuum dried for 24 h to obtain product 2.

[0055] S3: 0.1 g of product 2 and 20 mL of N,N-dimethylformamide were added to a round-bottom flask, stirred in a water bath at 60°C for 30 min, 0.045 mL of triethylamine and 0.065 g of N,N-dimethyl-1,3-propylenediamine were added, and stirring was continued for 48 h. After cooling, the product was dialyzed for 3 days with a molecular weight cutoff of 3500 Da. The product was filtered and lyophilized to obtain product 3.

[0056] S4: 0.1 g of product 3 and 10 mL of N,N-dimethylformamide were added to a round-bottom flask, stirred in an oil bath at 60°C, and then 6 mL of 1-n-bromobutane was added. The reaction was continued for 8 h. After the reaction was completed, the mixture was cooled, dialyzed for 3 days, rotary evaporated, filtered, and freeze-dried to obtain product 4.

[0057] S5: 0.1 g of product 4 was evacuated under an oil pump to replace nitrogen, 2 mL of tetrahydrofuran and 0.2 mL of isopropylmagnesium chloride were added, and the mixture was stirred. Subsequently, 0.011 g of Ni(dppp)Cl2 was added, and the reaction was continued for 2 h. The mixture was centrifuged and dried to obtain a composite polythiophene copolymer.

[0058] This embodiment discloses a highly flexible transparent conductive shielding film, composed of the following ingredients in parts by weight: 24 parts of modified epoxy resin, 1 part of composite polythiophene copolymer, 8 parts of ethylene-vinyl acetate copolymer, 2 parts of benzophenone, 3 parts of triallyl isocyanurate, 0.5 parts of toluene, 2 parts of N,N-dimethylformamide, 2 parts of dopamine hydrochloride, and 5 parts of tris(hydroxymethyl)aminomethane.

[0059] This embodiment discloses a method for preparing a highly flexible transparent conductive shielding film, comprising the following steps:

[0060] Step (1): Ethylene-vinyl acetate copolymer, benzophenone and triallyl isocyanurate are mixed for 7 hours and then dissolved in a mixed solution of toluene and N,N-dimethylformamide, and a modified epoxy resin and a composite polythiophene copolymer are added to obtain a fiber membrane precursor solution, and a composite fiber membrane is obtained by electrospinning technology, wherein the parameters of the electrospinning technology are: ambient temperature of 30° C., relative humidity of 45%, and a collection drum rotation speed of 120 rpm;

[0061] Step (2): dopamine hydrochloride and tris(hydroxymethyl)aminomethane) are mixed and added to deionized water, and stirred for 24 hours to obtain a dopamine solution. The composite fiber membrane is immersed in the dopamine solution and continuously stirred. After stirring, it is placed in deionized water for ultrasonic treatment for 10 minutes. After drying, a highly flexible transparent conductive shielding film is obtained.

[0062] Example 3

[0063] This embodiment discloses a method for preparing a modified epoxy resin, comprising the following steps:

[0064] Q1: 2.028 g of polyether diol with a relative molecular mass of 600 was placed in a vacuum drying oven at 100°C for 3 h and then mixed evenly with 1.347 g of 2,4-toluene diisocyanate. The mixture was then heated in a nitrogen atmosphere at 70°C for 8 h to obtain a polyurethane prepolymer.

[0065] Q2: Mix and stir the polyurethane prepolymer and bisphenol A diglycidyl ether, raise the temperature to 110°C, add 2-methyl-4-ethylimidazole to obtain a mixture, add 2,4-diisocyanate to the mixture dropwise using a constant pressure dropping funnel, and after the addition is complete, raise the temperature to 150°C for reaction to obtain a modified epoxy resin.

[0066] This embodiment discloses a method for preparing a composite polythiophene copolymer, comprising the following steps:

[0067] S1: Add 155 mL of tetrahydrofuran and 6 g of thiophene-3-acetic acid to a flask, and add 20 mL of triethylamine and 12.4 mL of pentafluorophenyl trifluoroacetate dropwise in an ice-water bath. After the addition is complete, stir for 2 h, rotary evaporation, add ethyl acetate to dissolve, wash, extract, dry for 24 h, filter, and purify to obtain product 1;

[0068] S2: 2.1 g of anhydrous ferric chloride and 32 mL of chloroform were stirred under argon for 30 min to obtain a suspension. 1.1 g of product 1 was dissolved in 12 mL of chloroform and quickly added to the suspension, stirred, and then methanol was added. The mixture was filtered, extracted for 3 days, and vacuum dried for 24 h to obtain product 2.

[0069] S3: 0.2 g of product 2 and 40 mL of N,N-dimethylformamide were added to a round-bottom flask, stirred in a water bath at 60°C for 30 min, 0.091 mL of triethylamine and 0.130 g of N,N-dimethyl-1,3-propylenediamine were added, and stirring was continued for 48 h. After cooling, the product was dialyzed for 3 days with a molecular weight cutoff of 3500 Da. The product was filtered and lyophilized to obtain product 3.

[0070] S4: 0.3 g of product 3 and 30 mL of N,N-dimethylformamide were added to a round-bottom flask, stirred in an oil bath at 60°C, and then 3 mL of 1-n-bromobutane was added. The reaction was continued for 8 h. After the reaction was completed, the mixture was cooled, dialyzed for 3 days, rotary evaporated, filtered, and freeze-dried to obtain product 4;

[0071] S5: 0.2 g of product 4 was evacuated under an oil pump to replace nitrogen, 4 mL of tetrahydrofuran and 0.4 mL of isopropylmagnesium chloride were added, and the mixture was stirred. Subsequently, 0.022 g of Ni(dppp)Cl2 was added, and the reaction was continued for 2 h. The mixture was centrifuged and dried to obtain a composite polythiophene copolymer.

[0072] This embodiment discloses a highly flexible transparent conductive shielding film, composed of the following ingredients in parts by weight: 36 parts of modified epoxy resin, 3 parts of composite polythiophene copolymer, 12 parts of ethylene-vinyl acetate copolymer, 3 parts of benzophenone, 1 part of triallyl isocyanurate, 1.1 parts of toluene, 3 parts of N,N-dimethylformamide, 5 parts of dopamine hydrochloride, and 2 parts of tris(hydroxymethyl)aminomethane.

[0073] This embodiment discloses a method for preparing a highly flexible transparent conductive shielding film, comprising the following steps:

[0074] Step (1): Ethylene-vinyl acetate copolymer, benzophenone and triallyl isocyanurate are mixed for 7 hours and then dissolved in a mixed solution of toluene and N,N-dimethylformamide, and a modified epoxy resin and a composite polythiophene copolymer are added to obtain a fiber membrane precursor solution, and a composite fiber membrane is obtained by electrospinning technology, wherein the parameters of the electrospinning technology are: ambient temperature of 30° C., relative humidity of 45%, and a collection drum rotation speed of 120 rpm;

[0075] Step (2): dopamine hydrochloride and tris(hydroxymethyl)aminomethane) are mixed and added to deionized water, and stirred for 24 hours to obtain a dopamine solution. The composite fiber membrane is immersed in the dopamine solution and continuously stirred. After stirring, it is placed in deionized water for ultrasonic treatment for 10 minutes. After drying, a highly flexible transparent conductive shielding film is obtained.

[0076] Example 4

[0077] This embodiment discloses a method for preparing a modified epoxy resin, comprising the following steps:

[0078] Q1: 2.028 g of polyether diol with a relative molecular mass of 600 was placed in a vacuum drying oven at 100°C for 3 hours and then mixed evenly with 1.218 g of 2,4-diisocyanatotoluene. The mixture was then heated in a nitrogen atmosphere at 70°C for 8 hours to obtain a polyurethane prepolymer.

[0079] Q2: Mix and stir the polyurethane prepolymer and bisphenol A diglycidyl ether, raise the temperature to 110°C, add 2-methyl-4-ethylimidazole to obtain a mixture, add 2,4-diisocyanate to the mixture dropwise using a constant pressure dropping funnel, and after the addition is complete, raise the temperature to 150°C for reaction to obtain a modified epoxy resin.

[0080] This embodiment discloses a method for preparing a composite polythiophene copolymer, comprising the following steps:

[0081] S1: 142 mL of tetrahydrofuran and 4.7 g of thiophene-3-acetic acid were added to a flask. 19.1 mL of triethylamine and 11.9 mL of pentafluorophenyl trifluoroacetate were added dropwise under an ice-water bath. After the addition was complete, the mixture was stirred for 2 h, rotary evaporated, and ethyl acetate was added for dissolution. The mixture was washed, extracted, dried for 24 h, filtered, and purified to obtain product 1.

[0082] S2: 2 g of anhydrous ferric chloride and 31 mL of chloroform were stirred under argon for 30 min to obtain a suspension. 1 g of product 1 was dissolved in 11 mL of chloroform and quickly added to the suspension, stirred, and then methanol was added. The mixture was filtered, extracted for 3 days, and vacuum dried for 24 h to obtain product 2.

[0083] S3: 0.11 g of product 2 and 25 mL of N,N-dimethylformamide were added to a round-bottom flask, stirred in a 60°C water bath for 30 min, 0.063 mL of triethylamine and 0.127 g of N,N-dimethyl-1,3-propylenediamine were added, and stirring was continued for 48 h. After cooling, the product was dialyzed for 3 days with a molecular weight cutoff of 3500 Da. The product was filtered and lyophilized to obtain product 3.

[0084] S4: 0.15 g of product 3 and 25 mL of N,N-dimethylformamide were added to a round-bottom flask, stirred in an oil bath at 60°C, and then 7 mL of 1-n-bromobutane was added. The reaction was continued for 8 h. After the reaction was completed, the mixture was cooled, dialyzed for 3 days, rotary evaporated, filtered, and freeze-dried to obtain product 4.

[0085] S5: 0.17 g of product 4 was evacuated under an oil pump to replace nitrogen, 2.5 mL of tetrahydrofuran and 0.35 mL of isopropylmagnesium chloride were added, and the mixture was stirred. Subsequently, 0.013 g of Ni(dppp)Cl2 was added, and the reaction was continued for 2 h. The mixture was centrifuged and dried to obtain a composite polythiophene copolymer.

[0086] This embodiment discloses a highly flexible transparent conductive shielding film, composed of the following components in parts by weight: 28 parts of modified epoxy resin, 2.5 parts of composite polythiophene copolymer, 13 parts of ethylene-vinyl acetate copolymer, 2.7 parts of benzophenone, 1.5 parts of triallyl isocyanurate, 0.9 parts of toluene, 1.2 parts of N,N-dimethylformamide, 4 parts of dopamine hydrochloride, and 3 parts of tris(hydroxymethyl)aminomethane.

[0087] This embodiment discloses a method for preparing a highly flexible transparent conductive shielding film, comprising the following steps:

[0088] Step (1): Ethylene-vinyl acetate copolymer, benzophenone and triallyl isocyanurate are mixed for 7 hours and then dissolved in a mixed solution of toluene and N,N-dimethylformamide, and a modified epoxy resin and a composite polythiophene copolymer are added to obtain a fiber membrane precursor solution, and a composite fiber membrane is obtained by electrospinning technology, wherein the parameters of the electrospinning technology are: ambient temperature of 30° C., relative humidity of 45%, and a collection drum rotation speed of 120 rpm;

[0089] Step (2): dopamine hydrochloride and tris(hydroxymethyl)aminomethane) are mixed and added to deionized water, and stirred for 24 hours to obtain a dopamine solution. The composite fiber membrane is immersed in the dopamine solution and continuously stirred. After stirring, it is placed in deionized water for ultrasonic treatment for 10 minutes. After drying, a highly flexible transparent conductive shielding film is obtained.

[0090] Comparative Example 1

[0091] Comparative Example 1 Compared with Example 1, in the preparation process of the modified epoxy resin in Comparative Example 1, 2,4-toluene diisocyanate was not added, and other conditions remained unchanged.

[0092] Comparative Example 2

[0093] Comparative Example 2 Compared with Example 1, in the preparation process of the modified epoxy resin in Comparative Example 2, no bisphenol A diglycidyl ether was added, and other conditions remained unchanged.

[0094] Comparative Example 3

[0095] Comparative Example 3 Compared with Example 1, in the preparation process of the composite polythiophene copolymer in Comparative Example 3, no thiophene-3-acetic acid was added, and other conditions remained unchanged.

[0096] Comparative Example 4

[0097] Comparative Example 4 Compared with Example 1, in the preparation process of the composite polythiophene copolymer in Comparative Example 4, no isopropyl magnesium chloride was added, and other conditions remained unchanged.

[0098] Comparative Example 5

[0099] Comparative Example 5 Compared with Example 1, in the preparation process of the composite polythiophene copolymer in Comparative Example 5, no Ni(dppp)Cl2 was added, and other conditions remained unchanged.

[0100] Comparative Example 6

[0101] Comparative Example 6 Compared with Example 1, in the preparation process of the transparent conductive shielding film in Comparative Example 6, no modified epoxy resin is added, and other conditions remain unchanged.

[0102] Comparative Example 7

[0103] Comparative Example 7 Compared with Example 1, in the preparation process of the transparent conductive shielding film in Comparative Example 7, no composite polythiophene copolymer is added, and other conditions remain unchanged.

[0104] Comparative Example 8

[0105] Comparative Example 8 Compared with Example 1, in the preparation process of the transparent conductive shielding film in Comparative Example 8, no dopamine solution was added, and other conditions remained unchanged.

[0106] The performance of the highly flexible transparent conductive shielding films prepared in Comparative Examples 1-4 and Examples 1-8 was tested. The tensile strength of the samples was tested in accordance with GB / T 13022-1991, the elongation at break of the samples was tested in accordance with GB / T 1040.3-2006, the shielding effect of the samples was tested in accordance with GB / T 30142-2013, and the high temperature resistance of the samples was tested in accordance with ASTM D648. The test results are shown in Table 1:

[0107]

[0108]

[0109] From the test results in Table 1, it can be seen that the transparent conductive shielding films prepared in Examples 1-4 of the present invention have excellent flexibility, shielding effect and high temperature resistance. From the comparison between Comparative Example 1 and Examples 1-4, it can be seen that the addition of 2,4-diisocyanatotoluene can effectively improve the flexibility and high temperature resistance of the transparent conductive shielding film; from the comparison between Comparative Example 2 and Examples 1-4, it can be seen that the addition of bisphenol A diglycidyl ether can effectively improve the flexibility and high temperature resistance of the transparent conductive shielding film; from the comparison between Comparative Example 3 and Examples 1-4, it can be seen that the addition of thiophene-3-acetic acid can effectively improve the shielding effect of the transparent conductive shielding film; from the comparison between Comparative Example 4 and Examples 1-4, it can be seen that the addition of isopropyl magnesium chloride can effectively improve the shielding effect of the transparent conductive shielding film. Effect; By comparing Comparative Example 5 with Examples 1-4, it can be seen that the addition of Ni(dppp)Cl2 can effectively improve the shielding effect of the transparent conductive shielding film; By comparing Comparative Example 6 with Examples 1-4, it can be seen that the addition of modified epoxy resin can effectively improve the flexibility and high temperature resistance of the transparent conductive shielding film; By comparing Comparative Example 7 with Examples 1-4, it can be seen that the addition of composite polythiophene copolymer can effectively improve the flexibility and high temperature resistance of the transparent conductive shielding film; By comparing Comparative Example 8 with Examples 1-4, it can be seen that the addition of dopamine solution can effectively improve the flexibility of the transparent conductive shielding film.

[0110] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

[0111] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A highly flexible transparent conductive shielding film, characterized in that: The invention is composed of the following components in parts by weight: 24-36 parts of modified epoxy resin, 1-3 parts of composite polythiophene copolymer, 8-13 parts of ethylene-vinyl acetate copolymer, 2-3 parts of benzophenone, 1-3 parts of triallyl isocyanurate, 0.5-1.1 parts of toluene, 1-3 parts of N,N-dimethylformamide, 2-5 parts of dopamine hydrochloride, and 2-5 parts of tris(hydroxymethyl)aminomethane; The preparation method of the modified epoxy resin comprises the following steps: Q1: The polyether diol is placed in a vacuum drying oven for vacuum dehydration and then mixed evenly with 2,4-diisocyanate toluene, followed by heating for reaction. After the reaction is completed, a polyurethane prepolymer is obtained; Q2: A polyurethane prepolymer and bisphenol A diglycidyl ether are mixed and stirred, the temperature is increased, 2-methyl-4-ethylimidazole is added to obtain a mixture, 2,4-diisocyanate is added dropwise to the mixture using a constant pressure dropping funnel, and after the addition is complete, the temperature is increased to react to obtain a modified epoxy resin; The preparation method of the composite polythiophene copolymer comprises the following steps: S1: Tetrahydrofuran and thiophene-3-acetic acid were added to a flask, and triethylamine and pentafluorophenyl trifluoroacetate were added dropwise under ice-water bath. After the addition was completed, the mixture was stirred, rotary evaporated, and ethyl acetate was added to dissolve the mixture. The mixture was washed, extracted, dried, filtered, and purified to obtain product 1. S2: Anhydrous ferric chloride and chloroform are stirred under argon protection to obtain a suspension, product 1 is dissolved in chloroform and quickly added to the suspension, stirred, and then methanol is added. The mixture is filtered, extracted, and dried in vacuo to obtain product 2; S3: Add product 2 and N,N-dimethylformamide to a round-bottom flask, stir in a water bath, add triethylamine and N,N-dimethyl-1,3-propylenediamine, continue stirring, cool, dialyze, filter, and lyophilize to obtain product 3; S4: Add product 3 and N,N-dimethylformamide to a round-bottom flask, stir in an oil bath, add 1-n-bromobutane, and continue the reaction. After the reaction is completed, cool, dialyze, rotary evaporate, filter, and freeze-dry to obtain product 4; S5: The product 4 was vacuumed under an oil pump to replace nitrogen, tetrahydrofuran and isopropylmagnesium chloride were added, and stirred, and then Ni(dppp)Cl2 was added, and the reaction was continued. The mixture was centrifuged and dried to obtain a composite polythiophene copolymer; The method for preparing the highly flexible transparent conductive shielding film comprises the following steps: Step (1): Ethylene-vinyl acetate copolymer, benzophenone and triallyl isocyanurate are mixed and dissolved in a mixed solution of toluene and N,N-dimethylformamide, and modified epoxy resin and composite polythiophene copolymer are added to obtain a fiber membrane precursor solution, and a composite fiber membrane is obtained by electrospinning technology; Step (2): dopamine hydrochloride and tris(hydroxymethyl)aminomethane) are mixed and added to deionized water, and stirred to obtain a dopamine solution. The composite fiber membrane is immersed in the dopamine solution and continuously stirred. After the stirring is completed, the composite fiber membrane is placed in deionized water for ultrasonic treatment. After drying, a highly flexible transparent conductive shielding film is obtained.

2. The highly flexible transparent conductive shielding film according to claim 1, characterized in that: In the Q1, the relative molecular mass of the polyether diol is 600, the temperature of the vacuum drying oven is 100-130°C, the time is 2-3h, the molar ratio of the polyether diol and 2,4-diisocyanate toluene is 1:(1.7-2.3), the heating reaction is carried out in a nitrogen-filled atmosphere, the heating temperature is 60-80°C, and the reaction time is 7-10h; in the Q2, the heating temperature is 90-110°C, and the heating temperature is 140-160°C.

3. The highly flexible transparent conductive shielding film according to claim 1, characterized in that: In S1, the amount ratio of tetrahydrofuran, thiophene-3-acetic acid, triethylamine and pentafluorophenyl trifluoroacetate is (140-160) mL: (4-6) g: (19-20) mL: (11.8-12.4) mL, the stirring time is 1-2 h, and the drying time is 20-24 h; in S2, the amount ratio of anhydrous ferric chloride and chloroform is (1.8-2.1) g: (28-32) mL, the stirring time is 30-45 min, the amount ratio of product 1 and chloroform is (0.8-1.1) g: (8-12) mL, the extraction time is 3-4 days, and the vacuum drying time is 20-24 h.

4. The highly flexible transparent conductive shielding film according to claim 1, characterized in that: In S3, the usage ratio of product 2, N,N-dimethylformamide, triethylamine and N,N-dimethyl-1,3-propylenediamine is (0.1-0.2) g: (20-40) mL: (0.045-0.091) mL: (0.065-0.131) g, the water bath temperature is 50-60°C, the stirring time is 30-40 min, the continued stirring time is 40-50 h, the dialysis molecular weight cutoff is 3500 Da, and the dialysis time is 3-5 days.

5. The highly flexible transparent conductive shielding film according to claim 1, characterized in that: In the S4, the amount ratio of the product 3, N,N-dimethylformamide and 1-bromobutane is (0.1-0.3) g: (10-30) mL: (3-9) mL, the oil bath temperature is 50-60°C, the reaction time is continued for 6-8 hours, and the dialysis time is 2-4 days; in the S5, the amount ratio of the product 4, tetrahydrofuran, isopropylmagnesium chloride and Ni(dppp)Cl2 is (0.1-0.2) g: (2-4) mL: (0.2-0.4) mL: (0.011-0.022) g, and the reaction time is continued for 1-3 hours.

6. The method for preparing a highly flexible transparent conductive shielding film according to any one of claims 1 to 5, wherein: The following steps are involved: Step (1): Ethylene-vinyl acetate copolymer, benzophenone and triallyl isocyanurate are mixed and dissolved in a mixed solution of toluene and N,N-dimethylformamide, and modified epoxy resin and composite polythiophene copolymer are added to obtain a fiber membrane precursor solution, and a composite fiber membrane is obtained by electrospinning technology; Step (2): dopamine hydrochloride and tris(hydroxymethyl)aminomethane) are mixed and added to deionized water, and stirred to obtain a dopamine solution. The composite fiber membrane is immersed in the dopamine solution and continuously stirred. After the stirring is completed, the composite fiber membrane is placed in deionized water for ultrasonic treatment. After drying, a highly flexible transparent conductive shielding film is obtained.

7. The method for preparing a highly flexible transparent conductive shielding film according to claim 6, wherein: In the step (1), the mixing time is 5-7 hours, and the parameters of the electrospinning technology are: the ambient temperature is 28-32° C., the relative humidity is 40-50%, and the rotation speed of the collecting drum is 100-120 rpm.

8. The method for preparing a highly flexible transparent conductive shielding film according to claim 6, wherein: In the step (2), the stirring time is 20-24 hours, and the ultrasonic treatment time is 5-10 minutes.

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