High-toughness photo-thermal dual-curing anisotropic conductive film and preparation method thereof
By employing a photothermal dual curing method and utilizing the cross-linked network structure of modified silver powder and organosilicon resin, the problems of environmental pollution and poor mechanical properties in the preparation process of existing conductive films have been solved, and a conductive film with high toughness and self-healing properties has been prepared.
Patent Information
- Application Number
- CN202511321864.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-16
- Publication Date
- 2025-11-11
AI Technical Summary
Existing anisotropic conductive films use volatile solvents during preparation, leading to environmental pollution. Furthermore, the high stiffness of the main chain of thermosetting resins results in poor mechanical properties and insufficient toughness.
A conductive film was prepared by using a mixture of bisphenol A epoxy acrylate resin, modified polyurethane, silicone resin and modified silver powder through a photothermal dual curing method. The mechanical properties were improved by utilizing the cross-linked network structure of modified silver powder and silicone resin, and the toughness was enhanced by the self-healing ability of modified polyurethane.
This approach achieves improved toughness and conductivity of the conductive film while reducing solvent usage, and also provides self-healing capabilities and enhanced mechanical properties.
Abstract
Description
Technical Field
[0001] This invention relates to the field of conductive film technology, specifically to a high-toughness photothermal dual-curing anisotropic conductive film and its preparation method. Background Technology
[0002] With the rapid development of technology, electronic products have had a tremendous impact on people's production and lives. Among them, the design of liquid crystal displays (LCDs) has made electronic products thinner, lighter, and more portable. As an important component of LCDs, anisotropic conductive film (ACF) has three functions: conductivity, insulation, and adhesion, ensuring the safety and reliability of LCDs.
[0003] Currently, commercially available ACF (Anisotropic Conductive Film) is composed of thermosetting resin, conductive particles, curing agents, and other additives. The typical solvent-curing process involves dissolving these components in solvents such as toluene, methyl ethyl ketone (MEK), or ethyl acetate, thoroughly stirring and degassing, coating the film onto a PET film, and then heating at high temperature to evaporate the solvent, thus producing ACF. This process uses a large amount of volatile solvents, posing a significant potential hazard to the environment. Furthermore, the main chain of the thermosetting resin used in commercially available ACF usually has a highly rigid benzene ring structure, resulting in a cured product with poor mechanical properties, exhibiting insufficient toughness and brittleness. Therefore, this invention prepares a photothermal dual-curing anisotropic conductive film with excellent electrical and mechanical properties. Summary of the Invention
[0004] The purpose of this invention is to provide a high-toughness photothermal dual-curing anisotropic conductive film and its preparation method, so as to solve the problems existing in the prior art.
[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A high-toughness photothermal dual-curing anisotropic conductive film is prepared by coating a mixture of bisphenol A epoxy acrylate resin, modified polyurethane, silicone resin, and modified silver powder onto a PET substrate and curing it.
[0006] As an optimization, the modified polyurethane is prepared by reacting isophorone diisocyanate with hydroxyl-terminated unsaturated polyether to generate a polyurethane prepolymer, which is then reacted with ethylenediamine.
[0007] As an optimization, the terminal hydroxyl unsaturated polyether is prepared by reacting 2-hydroxyethyl disulfide with glycidyl methacrylate.
[0008] As an optimization, the organosilicon resin is prepared by reacting 3-(2,3-epoxypropoxy)propyltrimethoxysilane and diphenylsilanediol.
[0009] As an optimization, the modified silver powder is prepared by reacting silver powder with vinyltriethoxysilane.
[0010] A method for preparing a high-toughness photothermal dual-curing anisotropic conductive film includes the following preparation steps: (1) Under a nitrogen atmosphere, the polyurethane prepolymer and ethylenediamine were mixed evenly at a molar ratio of isocyanate group to amino group of 1:(1~1.02). The mixture was stirred at 80~90℃ and 200~300r / min for 2~3h. N,N-dimethylformamide was removed by vacuum distillation. The mixture was then dried under vacuum at 60~70℃ for 8~10h to obtain the modified polyurethane. (2) Mix anhydrous ethanol and acetic acid at a mass ratio of 1: (0.05~0.06) until homogeneous, add vinyltriethoxysilane at a mass ratio of 0.004~0.006 times that of anhydrous ethanol, stir at 200~300 r / min for 15~20 min at room temperature, add silver powder at a mass ratio of 0.1~0.2 times that of anhydrous ethanol, stir at 200~300 r / min for 2~3 h at room temperature, add to a cell disruptor and mix for 4~6 min, let stand for 2~3 h, pour off the supernatant, and vacuum dry the lower precipitate at 40~50℃ for 10~12 h to obtain modified silver powder; (3) Under a nitrogen atmosphere, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, diphenylsilanediol and barium hydroxide are mixed evenly at a mass ratio of 1:(1.3~1.4):(0.004~0.005), stirred at 75~85℃ and 200~300r / min for 6~8h, and then dried under vacuum at 55~65℃ for 4~6h to obtain organosilicon resin; (4) The conductive adhesive paste is coated onto the PET substrate using a coating machine, exposed in a UV-LED curing machine for 4~6 min, and cured in a vacuum oven at 120~140℃ for 20~30 min to obtain a high-toughness photothermal dual-cured anisotropic conductive film.
[0011] As an optimization, the preparation steps of the polyurethane prepolymer in step (1) are as follows: Under a nitrogen atmosphere, isophorone diisocyanate and hydroxyl-terminated unsaturated polyether are mixed evenly according to the molar ratio of isocyanate group to hydroxyl group of 1:(0.6~0.7), and dibutyltin dilaurate and N,N-dimethylformamide at 0.006~0.008 times the mass of isophorone diisocyanate and 15~20 times the mass of isophorone diisocyanate are added. The mixture is stirred at 80~90℃ and 200~300r / min for 6~8h to obtain the polyurethane prepolymer.
[0012] As an optimization, the silver powder in step (2) has a particle size of 5 μm and was purchased from Zhejiang Manli Nanotechnology Co., Ltd.
[0013] As an optimization, the preparation steps of the conductive adhesive paste in step (4) are as follows: Bisphenol A epoxy acrylate resin, modified polyurethane, organosilicon resin, diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxychloride, azobisisobutyronitrile, 2,4,6-tris(dimethylaminomethyl)phenol, and anti-settling agent are mixed evenly in a mass ratio of 1:(0.7~0.8):(0.3~0.4):(0.07~0.08):(0.02~0.03):(0.015~0.02):(0.004~0.006). The mixture is stirred at 3000 r / min for 5~10 min at room temperature. Modified silver powder of 0.2~0.3 times the mass of bisphenol A epoxy acrylate resin is added. The mixture is stirred at 2500 r / min for 5~10 min at room temperature to obtain the conductive adhesive paste.
[0014] As an optimization, the preparation steps of the hydroxyl-terminated unsaturated polyether are as follows: Under a nitrogen atmosphere, 2-hydroxyethyl disulfide and potassium hydroxide are mixed evenly at a mass ratio of 1:(0.02~0.03), and stirred under vacuum at 80~90℃ and 200~300r / min for 40~50min. Glycidyl methacrylate is added dropwise at a rate of 5ml / min at a rate of 3.5~4 times the mass of 2-hydroxyethyl disulfide. The mixture is stirred at 80~90℃ and 200~300r / min for 6~8h. After cooling to room temperature, phosphoric acid is added dropwise at a mass of 0.03~0.04 times the mass of 2-hydroxyethyl disulfide. The mixture is stirred at 200~300r / min for 3~5min at room temperature. After filtration, the filtrate is washed 2~4 times with acetone and deionized water, and the acetone and deionized water are removed by rotary evaporation to obtain the hydroxyl-terminated unsaturated polyether.
[0015] As an optimization, the anti-settling agent is hydrophobic fumed silica.
[0016] Compared with the prior art, the beneficial effects achieved by the present invention are: In preparing a high-toughness photothermal dual-curing anisotropic conductive film, the present invention involves reacting 2-hydroxyethyl disulfide with glycidyl methacrylate to obtain a hydroxyl-terminated unsaturated polyether; reacting isophorone diisocyanate with the hydroxyl-terminated unsaturated polyether to generate a polyurethane prepolymer; reacting the polyurethane prepolymer with ethylenediamine to obtain a modified polyurethane; reacting silver powder with vinyltriethoxysilane to obtain modified silver powder; reacting 3-(2,3-epoxypropoxy)propyltrimethoxysilane and diphenylsilanediol to obtain an organosilicon resin; mixing bisphenol A epoxy acrylate resin, modified polyurethane, organosilicon resin, and modified silver powder to obtain a conductive paste; and coating the conductive paste onto a PET substrate and curing it to obtain a high-toughness photothermal dual-curing anisotropic conductive film.
[0017] First, 2-hydroxyethyl disulfide is reacted with glycidyl methacrylate to prepare a hydroxyl-terminated unsaturated polyether. Isophorone diisocyanate is then reacted with the hydroxyl-terminated unsaturated polyether to generate a polyurethane prepolymer. The polyurethane prepolymer is then reacted with ethylenediamine to prepare a modified polyurethane. The hydroxyl groups on the 2-hydroxyethyl disulfide react with the epoxy groups on glycidyl methacrylate to prepare a hydroxyl-terminated unsaturated polyether containing disulfide bonds and double bonds. This hydroxyl-terminated unsaturated polyether is then reacted with isophorone diisocyanate as a diol to introduce double and disulfide bonds into the polyurethane. The double bonds on the polyurethane are then reacted with modified silver powder and bisphenol A epoxy... The double bond reaction on the acrylic resin forms a cross-linked network structure, which improves the mechanical properties of the high-toughness photothermal dual-cured anisotropic conductive film. At the same time, the disulfide bonds on the polyurethane can be activated to break or recombine under heating conditions, giving the modified polyurethane a certain self-healing ability and improving the self-healing performance of the high-toughness photothermal dual-cured anisotropic conductive film. Ethylenediamine is added to the polyurethane as a chain extender, introducing amino groups onto the polyurethane. The amino groups and the epoxy groups on the organosilicon resin are cured under heating conditions, which further improves the mechanical properties of the high-toughness photothermal dual-cured anisotropic conductive film.
[0018] Secondly, modified silver powder was prepared by reacting silver powder with vinyltriethoxysilane. Silver powder has good electrical conductivity and was added as a conductive filler to the high-toughness photothermal dual-curing anisotropic conductive film, giving the high-toughness photothermal dual-curing anisotropic conductive film good electrical conductivity. However, silver powder is prone to agglomeration during use. Modifying the silver powder with vinyltriethoxysilane improved the dispersibility of the silver powder in the material. At the same time, double bonds were introduced on the surface of the silver powder, which reacted with the double bonds on polyurethane and bisphenol A epoxy acrylate resin to form a cross-linked network structure, improving the mechanical properties of the high-toughness photothermal dual-curing anisotropic conductive film.
[0019] Finally, 3-(2,3-epoxypropoxy)propyltrimethoxysilane and diphenylsilanediol were reacted to prepare an epoxy-containing organosilicon resin. The organosilicon resin contains flexible Si-O bonds. When mixed with bisphenol A epoxy acrylate resin, modified polyurethane, and modified silver powder, the internal stress of the cured product was reduced and the toughness of the cured product was improved, thereby improving the mechanical properties of the high-toughness photothermal dual-cured anisotropic conductive film. At the same time, the epoxy groups on the organosilicon resin and the amino groups on the modified polyurethane were cured under heating conditions, further improving the mechanical properties of the high-toughness photothermal dual-cured anisotropic conductive film. Detailed Implementation
[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0021] Example 1: A method for preparing a high-toughness photothermal dual-curing anisotropic conductive film includes the following preparation steps: (1) Under a nitrogen atmosphere, 2-hydroxyethyl disulfide and potassium hydroxide were mixed evenly at a mass ratio of 1:0.02. The mixture was stirred under vacuum at 200 r / min for 40 min at 80 °C. Glycidyl methacrylate was added dropwise at a rate of 5 ml / min at a rate of 3.5 times the mass of 2-hydroxyethyl disulfide. The mixture was stirred at 200 r / min for 6 h at 80 °C. After cooling to room temperature, phosphoric acid was added dropwise at a mass of 0.03 times the mass of 2-hydroxyethyl disulfide. The mixture was stirred at 200 r / min for 3 min at room temperature. The mixture was filtered, and the filtrate was washed twice with acetone and deionized water. The acetone and deionized water were removed by rotary evaporation to obtain a hydroxyl-terminated unsaturated polyether. Isophorone diisocyanate and hydroxyl-terminated unsaturated polyether were mixed evenly at a molar ratio of isocyanate group to hydroxyl group of 1:0.6. Dibutyltin dilaurate (0.006 times the mass of isophorone diisocyanate) and N,N-dimethylformamide (15 times the mass of isophorone diisocyanate) were added and stirred at 80℃ and 200 r / min for 6 h to obtain a polyurethane prepolymer. Under a nitrogen atmosphere, the polyurethane prepolymer and ethylenediamine were mixed evenly at a molar ratio of isocyanate group to amino group of 1:1. The mixture was stirred at 80℃ and 200 r / min for 2 h. N,N-dimethylformamide was removed by vacuum distillation, and the mixture was dried under vacuum at 60℃ for 8 h to obtain a modified polyurethane. (2) Mix anhydrous ethanol and acetic acid at a mass ratio of 1:0.05, add vinyltriethoxysilane at 0.004 times the mass of anhydrous ethanol, stir at 200 r / min for 15 min at room temperature, add silver powder at 0.1 times the mass of anhydrous ethanol, stir at 200 r / min for 2 h at room temperature, add to a cell disruptor and mix for 4 min, let stand for 2 h, pour off the supernatant, and vacuum dry the lower precipitate at 40℃ for 10 h to obtain modified silver powder; (3) Under a nitrogen atmosphere, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, diphenylsilanediol and barium hydroxide were mixed evenly in a mass ratio of 1:1.3:0.004, stirred at 75°C and 200r / min for 6h, and dried under vacuum at 55°C for 4h to obtain organosilicon resin. (4) Bisphenol A epoxy acrylate resin, modified polyurethane, silicone resin, diphenyl-(2,4,6-trimethylbenzoyl)oxyphosphorus, azobisisobutyronitrile, 2,4,6-tris(dimethylaminomethyl)phenol, and anti-settling agent are mixed evenly in a mass ratio of 1:0.7:0.3:0.07:0.02:0.015:0.004. The mixture is stirred at 3000 r / min for 5 min at room temperature. Modified silver powder with a mass of 0.2 times that of bisphenol A epoxy acrylate resin is added. The mixture is stirred at 2500 r / min for 5 min at room temperature to obtain a conductive paste. The conductive paste is coated onto a PET substrate using a coating machine. The substrate is exposed in a UV-LED curing machine for 4 min and cured in a vacuum oven at 120℃ for 20 min to obtain a high-toughness photothermal dual-cured anisotropic conductive film.
[0022] Example 2: A method for preparing a high-toughness photothermal dual-curing anisotropic conductive film includes the following preparation steps: (1) Under a nitrogen atmosphere, 2-hydroxyethyl disulfide and potassium hydroxide were mixed evenly at a mass ratio of 1:0.025. The mixture was stirred under vacuum at 250 r / min for 45 min at 85 °C. Glycidyl methacrylate was added dropwise at a rate of 5 ml / min at a rate of 3.8 times the mass of 2-hydroxyethyl disulfide. The mixture was stirred at 250 r / min for 7 h at 85 °C. After cooling to room temperature, phosphoric acid was added dropwise at a mass ratio of 0.035 times the mass of 2-hydroxyethyl disulfide. The mixture was stirred at 250 r / min for 4 min at room temperature. The mixture was filtered, and the filtrate was washed three times with acetone and deionized water. The acetone and deionized water were removed by rotary evaporation to obtain a hydroxyl-terminated unsaturated polyether. Under a nitrogen atmosphere, according to The isocyanate group to hydroxyl group molar ratio was 1:0.65. Isophorone diisocyanate and hydroxyl-terminated unsaturated polyether were mixed evenly, and dibutyltin dilaurate (0.007 times the mass of isophorone diisocyanate) and N,N-dimethylformamide (18 times the mass of isophorone diisocyanate) were added. The mixture was stirred at 85℃ and 250 r / min for 7 h to obtain a polyurethane prepolymer. Under a nitrogen atmosphere, the polyurethane prepolymer and ethylenediamine were mixed evenly at an isocyanate group to amino group molar ratio of 1:1.01. The mixture was stirred at 85℃ and 250 r / min for 2.5 h, and N,N-dimethylformamide was removed by vacuum distillation. The mixture was then vacuum dried at 65℃ for 9 h to obtain a modified polyurethane. (2) Mix anhydrous ethanol and acetic acid at a mass ratio of 1:0.055, add vinyltriethoxysilane at 0.005 times the mass of anhydrous ethanol, stir at 250 r / min for 18 min at room temperature, add silver powder at 0.15 times the mass of anhydrous ethanol, stir at 250 r / min for 2.5 h at room temperature, add to a cell disruptor and mix for 5 min, let stand for 2.5 h, pour off the supernatant, and vacuum dry the lower precipitate at 45℃ for 11 h to obtain modified silver powder; (3) Under a nitrogen atmosphere, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, diphenylsilanediol and barium hydroxide were mixed evenly in a mass ratio of 1:1.35:0.0045, stirred at 80°C and 250 r / min for 7 h, and then dried under vacuum at 60°C for 5 h to obtain organosilicon resin. (4) Bisphenol A epoxy acrylate resin, modified polyurethane, silicone resin, diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxide, azobisisobutyronitrile, 2,4,6-tris(dimethylaminomethyl)phenol, and anti-settling agent were mixed evenly at a mass ratio of 1:0.75:0.35:0.075:0.025:0.018:0.005. The mixture was stirred at 3000 r / min for 8 min at room temperature. Modified silver powder with a mass of 0.25 times that of bisphenol A epoxy acrylate resin was added. The mixture was stirred at 2500 r / min for 8 min at room temperature to obtain a conductive paste. The conductive paste was coated onto a PET substrate using a coating machine. The substrate was exposed in a UV-LED curing machine for 5 min and cured in a vacuum oven at 130℃ for 25 min to obtain a high-toughness photothermal dual-curing anisotropic conductive film.
[0023] Example 3: A method for preparing a high-toughness photothermal dual-curing anisotropic conductive film includes the following preparation steps: (1) Under a nitrogen atmosphere, 2-hydroxyethyl disulfide and potassium hydroxide were mixed evenly at a mass ratio of 1:0.03. The mixture was stirred under vacuum at 300 r / min for 50 min at 90 °C. Glycidyl methacrylate was added dropwise at a rate of 5 ml / min at a rate of 4 times the mass of 2-hydroxyethyl disulfide. The mixture was stirred at 300 r / min for 8 h at 90 °C. After cooling to room temperature, phosphoric acid was added dropwise at a mass ratio of 0.04 times the mass of 2-hydroxyethyl disulfide. The mixture was stirred at 300 r / min for 5 min at room temperature. The mixture was filtered, and the filtrate was washed four times with acetone and deionized water. The acetone and deionized water were removed by rotary evaporation to obtain a hydroxyl-terminated unsaturated polyether. Under a nitrogen atmosphere, according to isocyanate... A polyurethane prepolymer was prepared by mixing isophorone diisocyanate and terminal hydroxyl unsaturated polyether at a molar ratio of 1:0.7, adding dibutyltin dilaurate (0.008 times the mass of isophorone diisocyanate) and N,N-dimethylformamide (20 times the mass of isophorone diisocyanate), and stirring at 90°C and 300 r / min for 8 h. Under a nitrogen atmosphere, the polyurethane prepolymer and ethylenediamine were mixed at a molar ratio of isocyanate to amino groups of 1:1.02, and stirred at 90°C and 300 r / min for 3 h. The N,N-dimethylformamide was removed by vacuum distillation, and the mixture was then vacuum dried at 70°C for 10 h to obtain the modified polyurethane. (2) Mix anhydrous ethanol and acetic acid at a mass ratio of 1:0.06, add vinyltriethoxysilane at 0.006 times the mass of anhydrous ethanol, stir at 300 r / min for 20 min at room temperature, add silver powder at 0.2 times the mass of anhydrous ethanol, stir at 300 r / min for 3 h at room temperature, add to a cell disruptor and mix for 6 min, let stand for 3 h, pour off the supernatant, and vacuum dry the lower precipitate at 50 °C for 12 h to obtain modified silver powder; (3) Under a nitrogen atmosphere, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, diphenylsilanediol and barium hydroxide were mixed evenly in a mass ratio of 1:1.4:0.005, stirred at 85°C and 300r / min for 8h, and dried under vacuum at 65°C for 6h to obtain organosilicon resin. (4) Bisphenol A epoxy acrylate resin, modified polyurethane, silicone resin, diphenyl-(2,4,6-trimethylbenzoyl)oxyphosphorus, azobisisobutyronitrile, 2,4,6-tris(dimethylaminomethyl)phenol, and anti-settling agent are mixed evenly in a mass ratio of 1:0.8:0.4:0.08:0.03:0.02:0.006. The mixture is stirred at 3000 r / min for 10 min at room temperature. Modified silver powder with a mass of 0.3 times that of bisphenol A epoxy acrylate resin is added. The mixture is stirred at 2500 r / min for 10 min at room temperature to obtain a conductive paste. The conductive paste is coated onto a PET substrate using a coating machine. The substrate is exposed in a UV-LED curing machine for 6 min and cured in a vacuum oven at 140℃ for 30 min to obtain a high-toughness photothermal dual-curing anisotropic conductive film.
[0024] Comparative Example 1: The difference between the preparation method of the high-toughness photothermal dual-curing anisotropic conductive film in Comparative Example 1 and Example 2 lies in the different step (1). Step (1) is modified as follows: Under a nitrogen atmosphere, isophorone diisocyanate and polytetrahydrofuran diol are mixed evenly at a molar ratio of isocyanate group to hydroxyl group of 1:0.65. Dibutyltin dilaurate (0.007 times the mass of isophorone diisocyanate) and N,N-dimethylformamide (18 times the mass of isophorone diisocyanate) are added and stirred at 85°C and 250 r / min for 7 h to obtain a polyurethane prepolymer. Under a nitrogen atmosphere, the polyurethane prepolymer and ethylenediamine are mixed evenly at a molar ratio of isocyanate group to amino group of 1:1.01. The mixture is stirred at 85°C and 250 r / min for 2.5 h. N,N-dimethylformamide is removed by vacuum distillation, and the mixture is dried under vacuum at 65°C for 9 h to obtain a modified polyurethane. The remaining steps are the same as in Example 2.
[0025] Comparative Example 2: The difference between the preparation method of the high-toughness photothermal dual-curing anisotropic conductive film in Comparative Example 2 and Example 2 lies in the different step (1). Step (1) is modified as follows: Under a nitrogen atmosphere, 2-hydroxyethyl disulfide and potassium hydroxide are mixed evenly at a mass ratio of 1:0.025. The mixture is then stirred under vacuum at 85°C and 250 r / min for 45 min. Glycidyl methacrylate is added dropwise at a rate of 5 ml / min at a rate of 3.8 times the mass of 2-hydroxyethyl disulfide. The mixture is stirred at 85°C and 250 r / min for 7 h. After cooling to room temperature, phosphoric acid is added dropwise at a mass ratio of 0.035 times the mass of 2-hydroxyethyl disulfide. The mixture is stirred at 250 r / min for 4 min at room temperature. The mixture is then filtered, and the resulting filtrate is washed three times with acetone and deionized water. The acetone and deionized water are removed by rotary evaporation. Deionized water was used to prepare a hydroxyl-terminated unsaturated polyether. Under a nitrogen atmosphere, isophorone diisocyanate and the hydroxyl-terminated unsaturated polyether were mixed evenly at a molar ratio of isocyanate groups to hydroxyl groups of 1:0.65. Dibutyltin dilaurate (0.007 times the mass of isophorone diisocyanate) and N,N-dimethylformamide (18 times the mass of isophorone diisocyanate) were added. The mixture was stirred at 85°C and 250 rpm for 7 h to obtain a polyurethane prepolymer. Under a nitrogen atmosphere, the polyurethane prepolymer and 1,4-butanediol were mixed evenly at a molar ratio of isocyanate groups to amino groups of 1:1.01. The mixture was stirred at 85°C and 250 rpm for 2.5 h. N,N-dimethylformamide was removed by vacuum distillation, and the mixture was dried under vacuum at 65°C for 9 h to obtain the modified polyurethane. The remaining steps were the same as in Example 2.
[0026] Comparative Example 3: The preparation method of the high-toughness photothermal dual-curing anisotropic conductive film in Comparative Example 3 differs from that in Example 2 in that step (2) is omitted, and step (4) is modified as follows: bisphenol A epoxy acrylate resin, modified polyurethane, silicone resin, diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxide, azobisisobutyronitrile, 2,4,6-tris(dimethylaminomethyl)phenol, and anti-settling agent are mixed in a mass ratio of 1:0.75:0.35:0.075:0.025:0.01 Mix 8:0.005 evenly, stir at 3000 rpm for 8 minutes at room temperature, add 0.25 times the weight of silver powder to the bisphenol A epoxy acrylate resin, and stir at 2500 rpm for 8 minutes at room temperature to obtain a conductive paste. Coat the conductive paste onto a PET substrate using a coating machine, expose it in a UV-LED curing machine for 5 minutes, and cure it in a vacuum oven at 130℃ for 25 minutes to obtain a high-toughness photothermal dual-cured anisotropic conductive film. The remaining steps are the same as in Example 2.
[0027] Comparative Example 4 The preparation method of the high-toughness photothermal dual-curing anisotropic conductive film in Comparative Example 4 differs from that in Example 2 in step (2). Step (2) is changed to mixing anhydrous ethanol and acetic acid at a mass ratio of 1:0.055, adding 0.005 times the mass of anhydrous ethanol in vinyltriethoxysilane, stirring at 250 r / min for 18 min at room temperature, adding 0.15 times the mass of anhydrous ethanol in copper powder, stirring at 250 r / min for 2.5 h at room temperature, adding to a cell disruptor and mixing for 5 min, letting stand for 2.5 h, pouring off the supernatant, and vacuum drying the lower precipitate at 45 °C for 11 h to obtain modified copper powder; the particle size of the copper powder is 5 μm. The remaining steps are the same as in Example 2.
[0028] Comparative Example 5 The preparation method of the high-toughness photothermal dual-curing anisotropic conductive film in Comparative Example 5 differs from that in Example 2 in that step (3) is omitted, and step (4) is modified as follows: bisphenol A epoxy acrylate resin, modified polyurethane, diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxide, azobisisobutyronitrile, 2,4,6-tris(dimethylaminomethyl)phenol, and anti-settling agent are mixed in a mass ratio of 1:0.75:0.075:0.025:0.018:0.005 Mix thoroughly and stir at 3000 rpm for 8 minutes at room temperature. Add 0.25 times the mass of modified silver powder to the bisphenol A epoxy acrylate resin and stir at 2500 rpm for 8 minutes at room temperature to obtain a conductive paste. Coat the conductive paste onto a PET substrate using a coating machine, expose it in a UV-LED curing machine for 5 minutes, and cure it in a vacuum oven at 130°C for 25 minutes to obtain a high-toughness photothermal dual-cured anisotropic conductive film. The remaining steps are the same as in Example 2.
[0029] Test Example 1: Conductivity test: The high-toughness photothermal dual-cured anisotropic conductive film was tested using a digital multimeter in accordance with the American ASTM D2739-72 (1998) standard. The resistance value of the high-toughness photothermal dual-cured anisotropic conductive film was measured.
[0030] The high-toughness photothermal dual-cured anisotropic conductive films obtained in each embodiment and comparative example were made into samples with a size of 160mm×10mm×2mm. Copper foil sheets of 30mm×30mm×0.05mm were placed at both ends of the sample as leads for resistance testing. After fixing a glass sheet of the same size on top using dovetail clips, the resistance test was performed.
[0031] The results are shown in Table 1.
[0032] Table 1 ; A comparison of the experimental data from Examples 1-3 and Comparative Examples 1-5 in Table 1 reveals that the high-toughness photothermal dual-curing anisotropic conductive film prepared by the present invention has good electrical conductivity.
[0033] By comparison, the resistivity of Examples 1-3 is lower than that of Comparative Examples 2-3, indicating that silver powder has good conductivity. As a conductive filler, it is added to the high-toughness photothermal dual-curing anisotropic conductive film, giving the high-toughness photothermal dual-curing anisotropic conductive film good conductivity. However, silver powder is prone to agglomeration during use, which reduces conductivity. Modifying silver powder with vinyltriethoxysilane improves the dispersibility of silver powder in the material, thereby improving the conductivity of the high-toughness photothermal dual-curing anisotropic conductive film.
[0034] Test Example 2: Mechanical properties and self-healing properties testing: The specific testing method is as follows: Mechanical property testing method: The high-toughness photothermal dual-cured anisotropic conductive films obtained in each embodiment and the comparative example were respectively made into test samples of 10cm×10mm×1mm. The test was carried out in accordance with GB / T1040.2-2022, with a tensile speed of 50mm / min, and the tensile strength M was tested.
[0035] Self-healing performance test method: The high-toughness photothermal dual-cured anisotropic conductive films obtained in each embodiment and the comparative example were respectively made into test samples of 10cm×10mm×1mm. After being cut in the middle and aligned, they were placed at 60℃ for 36h for self-healing. The tensile strength N was tested again, and the self-healing efficiency was calculated as N / M×100%.
[0036] The results are shown in Table 2.
[0037] Table 2 ; A comparison of the experimental data from Examples 1-3 and Comparative Examples 1-5 in Table 2 reveals that the high-toughness photothermal dual-curing anisotropic conductive film prepared by the present invention possesses excellent mechanical properties and self-healing properties.
[0038] By comparison, the tensile strength of Examples 1-3 is greater than that of Comparative Examples 1 and 3, indicating that the double bonds on the modified polyurethane react with the double bonds on the modified silver powder and bisphenol A epoxy acrylate resin to form a cross-linked network structure, which improves the mechanical properties of the high-toughness photothermal dual-cured anisotropic conductive film.
[0039] By comparison, the tensile strength of Examples 1-3 is greater than that of Comparative Examples 2 and 5, indicating that the silicone resin contains flexible Si-O bonds. When mixed with bisphenol A epoxy acrylate resin, modified polyurethane, and modified silver powder, the internal stress of the cured product is reduced and the toughness of the cured product is improved, thereby improving the mechanical properties of the high-toughness photothermal dual-cured anisotropic conductive film. At the same time, the epoxy groups on the silicone resin and the amino groups on the modified polyurethane are cured under heating conditions, which further improves the mechanical properties of the high-toughness photothermal dual-cured anisotropic conductive film.
[0040] By comparison, the self-healing efficiency of Examples 1-3 is greater than that of Comparative Example 1, indicating that the disulfide bonds on the modified polyurethane can be activated to break or recombine under heating conditions, thus giving the modified polyurethane a certain self-healing ability and improving the self-healing performance of the high-toughness photothermal dual-cured anisotropic conductive film.
[0041] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A high-toughness photothermal dual-curing anisotropic conductive film, characterized in that, The high-toughness photothermal dual-curing anisotropic conductive film is prepared by mixing bisphenol A epoxy acrylate resin, modified polyurethane, silicone resin, and modified silver powder, coating it onto a PET substrate, and then curing it. The modified polyurethane is prepared by reacting isophorone diisocyanate with hydroxyl-terminated unsaturated polyether to generate a polyurethane prepolymer, which is then reacted with ethylenediamine. The terminal hydroxyl unsaturated polyether is prepared by reacting 2-hydroxyethyl disulfide with glycidyl methacrylate. The organosilicon resin is prepared by reacting 3-(2,3-epoxypropoxy)propyltrimethoxysilane and diphenylsilanediol. The modified silver powder is prepared by reacting silver powder with vinyltriethoxysilane.
2. A method for preparing a high-toughness photothermal dual-curing anisotropic conductive film, characterized in that, The preparation steps include the following: (1) Under a nitrogen atmosphere, the polyurethane prepolymer and ethylenediamine were mixed evenly at a molar ratio of isocyanate group to amino group of 1: (1~1.02). The mixture was stirred and reacted at 80~90℃ for 2~3h. The mixture was then distilled under reduced pressure and dried to obtain the modified polyurethane. (2) Mix anhydrous ethanol and acetic acid at a mass ratio of 1: (0.05~0.06) until homogeneous, add vinyltriethoxysilane at a mass ratio of 0.004~0.006 times that of anhydrous ethanol, stir for 15~20 min at room temperature, add silver powder at a mass ratio of 0.1~0.2 times that of anhydrous ethanol, stir for 2~3 h at room temperature, add to a cell disruptor and mix for 4~6 min, let stand and dry to obtain modified silver powder; (3) Under a nitrogen atmosphere, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, diphenylsilanediol and barium hydroxide are mixed evenly in a mass ratio of 1:(1.3~1.4):(0.004~0.005), stirred and reacted at 75~85℃ for 6~8h, and dried to obtain organosilicon resin. (4) The conductive adhesive paste is coated onto the PET substrate using a coating machine, exposed in a UV-LED curing machine for 4~6 min, and cured in a vacuum oven at 120~140℃ for 20~30 min to obtain a high-toughness photothermal dual-cured anisotropic conductive film.
3. The method for preparing a high-toughness photothermal dual-curing anisotropic conductive film according to claim 2, characterized in that, The preparation steps of the polyurethane prepolymer in step (1) are as follows: Under a nitrogen atmosphere, isophorone diisocyanate and hydroxyl-terminated unsaturated polyether are mixed evenly according to the molar ratio of isocyanate group to hydroxyl group of 1:(0.6~0.7), and dibutyltin dilaurate and N,N-dimethylformamide are added at 0.006~0.008 times the mass of isophorone diisocyanate and 15~20 times the mass of isophorone diisocyanate. The mixture is stirred and reacted at 80~90℃ for 6~8h to obtain the polyurethane prepolymer.
4. The method for preparing a high-toughness photothermal dual-curing anisotropic conductive film according to claim 2, characterized in that, The silver powder in step (2) has a particle size of 5 μm.
5. The method for preparing a high-toughness photothermal dual-curing anisotropic conductive film according to claim 2, characterized in that, The preparation steps of the conductive adhesive paste in step (4) are as follows: Bisphenol A epoxy acrylate resin, modified polyurethane, organosilicon resin, diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxychloride, azobisisobutyronitrile, 2,4,6-tris(dimethylaminomethyl)phenol, and anti-settling agent are mixed evenly in a mass ratio of 1:(0.7~0.8):(0.3~0.4):(0.07~0.08):(0.02~0.03):(0.015~0.02):(0.004~0.006). The mixture is stirred for 5~10 min at room temperature. Modified silver powder with a mass of 0.2~0.3 times that of bisphenol A epoxy acrylate resin is added. The mixture is stirred for 5~10 min at room temperature to obtain the conductive adhesive paste.
6. The method for preparing a high-toughness photothermal dual-curing anisotropic conductive film according to claim 3, characterized in that, The preparation steps of the terminal hydroxyl unsaturated polyether are as follows: Under a nitrogen atmosphere, 2-hydroxyethyl disulfide and potassium hydroxide are mixed evenly at a mass ratio of 1:(0.02~0.03), and stirred under vacuum at 80~90℃ for 40~50 min. Glycidyl methacrylate is added dropwise at a rate of 5 ml / min at a mass ratio of 3.5~4 times that of 2-hydroxyethyl disulfide. The mixture is stirred and reacted at 80~90℃ for 6~8 h. After cooling to room temperature, phosphoric acid is added dropwise at a mass ratio of 0.03~0.04 times that of 2-hydroxyethyl disulfide. The mixture is stirred at room temperature for 3~5 min, filtered, washed, and rotary evaporated to obtain the terminal hydroxyl unsaturated polyether.
7. The method for preparing a high-toughness photothermal dual-curing anisotropic conductive film according to claim 5, characterized in that, The anti-settling agent is hydrophobic fumed silica.